diff --git a/.github/scripts/tests/test_release_workflow.py b/.github/scripts/tests/test_release_workflow.py
index b608b6c0f69..c0478fea8ad 100644
--- a/.github/scripts/tests/test_release_workflow.py
+++ b/.github/scripts/tests/test_release_workflow.py
@@ -67,6 +67,14 @@ def test_cosign_is_verified_before_release_publication(self):
             )
             self.assertLess(restore_position, publish_position)
 
+    def test_cosign_signing_retries_transient_service_failures(self):
+        self.assertEqual(self.workflow.count("for attempt in 1 2 3; do"), 3)
+        self.assertEqual(
+            self.workflow.count('echo "Cosign signing failed after $attempt attempts"'),
+            3,
+        )
+        self.assertEqual(self.workflow.count("sleep $((attempt * 15))"), 3)
+
     def test_github_release_uses_the_git_tag_not_the_product_version(self):
         self.assertIn('gh release create "$GIT_TAG"', self.workflow)
         self.assertIn("--verify-tag", self.workflow)
diff --git a/.github/workflows/build-branch.yml b/.github/workflows/build-branch.yml
index 8f27d0230ce..6b386d927d0 100644
--- a/.github/workflows/build-branch.yml
+++ b/.github/workflows/build-branch.yml
@@ -365,7 +365,18 @@ jobs:
         env:
           DIGEST: ${{ steps.build.outputs.digest }}
           IMAGE: ${{ env.IMAGE_PREFIX }}${{ matrix.image }}
-        run: cosign sign --yes "${IMAGE}@${DIGEST}"
+        run: |
+          set -euo pipefail
+          for attempt in 1 2 3; do
+            if cosign sign --yes "${IMAGE}@${DIGEST}"; then
+              exit 0
+            fi
+            if [[ "$attempt" -eq 3 ]]; then
+              echo "Cosign signing failed after $attempt attempts" >&2
+              exit 1
+            fi
+            sleep $((attempt * 15))
+          done
 
       - name: Verify release image signature
         if: needs.setup.outputs.is_release == 'true'
@@ -468,7 +479,18 @@ jobs:
         env:
           DIGEST: ${{ steps.build.outputs.digest }}
           IMAGE: ${{ env.IMAGE_PREFIX }}aio
-        run: cosign sign --yes "${IMAGE}@${DIGEST}"
+        run: |
+          set -euo pipefail
+          for attempt in 1 2 3; do
+            if cosign sign --yes "${IMAGE}@${DIGEST}"; then
+              exit 0
+            fi
+            if [[ "$attempt" -eq 3 ]]; then
+              echo "Cosign signing failed after $attempt attempts" >&2
+              exit 1
+            fi
+            sleep $((attempt * 15))
+          done
 
       - name: Verify release image signature
         if: needs.setup.outputs.is_release == 'true'
@@ -614,7 +636,16 @@ jobs:
           fi
 
           chart_ref="ghcr.io/szymczag/charts/hangar@${chart_digest}"
-          cosign sign --yes "$chart_ref"
+          for attempt in 1 2 3; do
+            if cosign sign --yes "$chart_ref"; then
+              break
+            fi
+            if [[ "$attempt" -eq 3 ]]; then
+              echo "Cosign signing failed after $attempt attempts" >&2
+              exit 1
+            fi
+            sleep $((attempt * 15))
+          done
           cosign verify \
             --certificate-identity "$CERTIFICATE_IDENTITY" \
             --certificate-oidc-issuer "https://token.actions.githubusercontent.com" \
diff --git a/README.md b/README.md
index 11b02e961c0..be1457456c8 100644
--- a/README.md
+++ b/README.md
@@ -54,7 +54,7 @@ the table marks them as available.
 ## Deployment
 
 - [Docker deployment](deployments/cli/community/README.md)
-- [Kubernetes and Helm](docs/kubernetes/README.md) — `0.1.0-rc.28`
+- [Kubernetes and Helm](docs/kubernetes/README.md) — `0.1.0-rc.29`
   evaluation release; production support gates remain open.
 - [Amazon SES, deliverability, and OpenPGP email](docs/aws-ses-email-operations.md)
   — secure transactional-email configuration and operations.
@@ -170,7 +170,7 @@ Install Cosign, obtain the digest for the version you intend to deploy, and veri
 both the exact workflow identity and GitHub's OIDC issuer:
 
 ```sh
-VERSION=v0.1.0-rc.28
+VERSION=v0.1.0-rc.29
 GIT_TAG=hangar-$VERSION
 DIGEST=sha256:replace-with-the-published-digest
 IMAGE=ghcr.io/szymczag/hangar-api
diff --git a/charts/hangar/README.md b/charts/hangar/README.md
index 1e5ce28ffb2..576b4a786da 100644
--- a/charts/hangar/README.md
+++ b/charts/hangar/README.md
@@ -7,7 +7,7 @@ published as an OCI artifact at:
 oci://ghcr.io/szymczag/charts/hangar
 ```
 
-The latest published chart is `0.1.0-rc.28` (`appVersion: v0.1.0-rc.28`). Its
+The latest published chart is `0.1.0-rc.29` (`appVersion: v0.1.0-rc.29`). Its
 evaluation profile is live-qualified on AMD64. It is a prerelease and is not yet
 supported for production. Release packaging stages these versions and immutable
 image digests from the release tag; source defaults remain fail-closed.
@@ -27,17 +27,18 @@ Inspect the published chart without registry credentials:
 
 ```bash
 helm show chart oci://ghcr.io/szymczag/charts/hangar \
-  --version 0.1.0-rc.28
+  --version 0.1.0-rc.29
 ```
 
-Do not use `0.1.0-rc.1`, `0.1.0-rc.2`, `0.1.0-rc.20`, `0.1.0-rc.24`, or
-`0.1.0-rc.25`; those immutable versions were consumed by incomplete release
-attempts. `0.1.0-rc.24` and `0.1.0-rc.25` each published only a subset of their
-container sets and no chart. `0.1.0-rc.27` is the immediately previous complete
+Do not use `0.1.0-rc.1`, `0.1.0-rc.2`, `0.1.0-rc.20`, `0.1.0-rc.24`,
+`0.1.0-rc.25`, or `0.1.0-rc.28`; those immutable versions were consumed by
+incomplete release attempts. `0.1.0-rc.24`, `0.1.0-rc.25`, and `0.1.0-rc.28`
+each published only a subset of their container sets and no chart or GitHub
+Release. `0.1.0-rc.27` is the immediately previous complete
 publication, but it predates the signed preview grant and transactional duplicate
-admission controls in `rc.28`.
+admission controls in `rc.29`.
 Earlier `rc.12` through `rc.17` additionally contain frontend migration failures.
-Use `0.1.0-rc.28`; there is no security-equivalent
+Use `0.1.0-rc.29`; there is no security-equivalent
 rollback target among the earlier release candidates.
 
 ## Deployment profiles
@@ -114,8 +115,8 @@ digests for the five Hangar application images. The source chart intentionally
 contains all-zero application digests so an unstaged source checkout fails
 closed.
 
-Release `0.1.0-rc.28` is available from the
-[GitHub Release](https://github.com/szymczag/hangar/releases/tag/hangar-v0.1.0-rc.28)
+Release `0.1.0-rc.29` is available from the
+[GitHub Release](https://github.com/szymczag/hangar/releases/tag/hangar-v0.1.0-rc.29)
 and GHCR. Follow the [verification guide](../../docs/kubernetes/security.md)
 before admitting the package to a controlled environment.
 
diff --git a/docs/kubernetes/README.md b/docs/kubernetes/README.md
index 7c5bf62dfbf..a9370c917cc 100644
--- a/docs/kubernetes/README.md
+++ b/docs/kubernetes/README.md
@@ -6,7 +6,7 @@ Hangar publishes a Helm chart for Kubernetes at:
 oci://ghcr.io/szymczag/charts/hangar
 ```
 
-The current release is `0.1.0-rc.28`. It is qualified for evaluation on
+The current release is `0.1.0-rc.29`. It is qualified for evaluation on
 AMD64 Kubernetes clusters. It is not yet a supported production release.
 
 > [!IMPORTANT]
@@ -44,7 +44,7 @@ only to review and help qualify the production profile.
 
 ## Compatibility
 
-The `0.1.0-rc.28` qualification boundary is:
+The `0.1.0-rc.29` qualification boundary is:
 
 | Item                   | Qualified boundary                                               |
 | ---------------------- | ---------------------------------------------------------------- |
@@ -110,23 +110,23 @@ The product, chart, and Git identifiers are deliberately different:
 
 | Identifier         | Current value                                |
 | ------------------ | -------------------------------------------- |
-| Product version    | `v0.1.0-rc.28`                               |
-| Helm chart version | `0.1.0-rc.28`                                |
-| Git tag            | `hangar-v0.1.0-rc.28`                        |
-| OCI chart          | `ghcr.io/szymczag/charts/hangar:0.1.0-rc.28` |
-
-`rc.1`, `rc.2`, `rc.20`, `rc.24`, and `rc.25` were consumed by incomplete publication
-attempts. Do not use them. `rc.27` is the immediately previous complete publication, but it
-predates the signed preview grant and transactional duplicate admission controls in `rc.28`.
+| Product version    | `v0.1.0-rc.29`                               |
+| Helm chart version | `0.1.0-rc.29`                                |
+| Git tag            | `hangar-v0.1.0-rc.29`                        |
+| OCI chart          | `ghcr.io/szymczag/charts/hangar:0.1.0-rc.29` |
+
+`rc.1`, `rc.2`, `rc.20`, `rc.24`, `rc.25`, and `rc.28` were consumed by incomplete
+publication attempts. Do not use them. `rc.27` is the immediately previous complete publication, but it
+predates the signed preview grant and transactional duplicate admission controls in `rc.29`.
 Earlier `rc.12` through `rc.17` additionally contain frontend migration failures.
 There is no security-equivalent rollback target among the earlier release
 candidates. Published versions are immutable and are never repaired in place. In
-particular, `rc.24` and `rc.25` each published only a subset of their container
-sets and published no chart or GitHub Release.
+particular, `rc.24`, `rc.25`, and `rc.28` each published only a subset of their
+container sets and published no chart or GitHub Release.
 
 ## Documentation
 
-- [Release `v0.1.0-rc.28` notes](../releases/hangar-v0.1.0-rc.28.md) — review
+- [Release `v0.1.0-rc.29` notes](../releases/hangar-v0.1.0-rc.29.md) — review
   security changes, migrations, compatibility, limitations, and rollback.
 - [Install the evaluation profile](evaluation-install.md) — complete a first
   installation in a dedicated namespace.
@@ -151,7 +151,7 @@ Pod Security, migrations, HTTPS ingress, WebSockets, positive and negative
 network-policy checks, dependency connectivity, object-storage persistence, an
 atomic upgrade, rollback-on-failure behavior, uninstall, and retained PVCs.
 
-The public `rc.28` chart archive, OCI chart, and digest-pinned Hangar images are
+The public `rc.29` chart archive, OCI chart, and digest-pinned Hangar images are
 anonymously downloadable. The release workflow also created provenance
 attestations and keyless Cosign signatures.
 
diff --git a/docs/kubernetes/configuration.md b/docs/kubernetes/configuration.md
index 257c525a80d..aa1dfbeab67 100644
--- a/docs/kubernetes/configuration.md
+++ b/docs/kubernetes/configuration.md
@@ -373,7 +373,7 @@ global:
 Use a component's `image.pullSecrets` for a narrower credential. Worker, beat,
 and migrator Pods use `api.image.pullSecrets` because they run the API image.
 Public release images currently pull anonymously, so a GHCR credential is not
-required for `0.1.0-rc.28`.
+required for `0.1.0-rc.29`.
 
 ## Replicas and disruption budgets
 
@@ -400,7 +400,7 @@ spread, and a termination grace period. Component templates combine these values
 with their security constraints.
 
 Evaluation dependencies are fixed to `kubernetes.io/arch: amd64`. All application
-images in `0.1.0-rc.28` are also AMD64-only.
+images in `0.1.0-rc.29` are also AMD64-only.
 
 ## Evaluation storage
 
diff --git a/docs/kubernetes/evaluation-install.md b/docs/kubernetes/evaluation-install.md
index 309211e0286..099e10ecfaa 100644
--- a/docs/kubernetes/evaluation-install.md
+++ b/docs/kubernetes/evaluation-install.md
@@ -1,6 +1,6 @@
 # Install Hangar for evaluation
 
-This tutorial installs Hangar `0.1.0-rc.28` in a dedicated namespace with bundled,
+This tutorial installs Hangar `0.1.0-rc.29` in a dedicated namespace with bundled,
 persistent PostgreSQL, Valkey, RabbitMQ, and object storage. When complete, you
 will have a TLS-enabled Hangar instance suitable for evaluation and compatibility
 testing.
@@ -26,7 +26,7 @@ You need:
 Set the release parameters used throughout this tutorial:
 
 ```bash
-export CHART_VERSION=0.1.0-rc.28
+export CHART_VERSION=0.1.0-rc.29
 export RELEASE_NAME=hangar
 export NAMESPACE=hangar-evaluation
 export HANGAR_HOST=hangar-evaluation.example.com
@@ -43,10 +43,10 @@ helm show chart oci://ghcr.io/szymczag/charts/hangar \
   --version "$CHART_VERSION"
 ```
 
-Confirm the output reports chart version `0.1.0-rc.28`, application version
-`v0.1.0-rc.28`, and the expected Kubernetes version constraint.
+Confirm the output reports chart version `0.1.0-rc.29`, application version
+`v0.1.0-rc.29`, and the expected Kubernetes version constraint.
 
-For higher-assurance environments, complete [artifact verification](security.md#verify-release-010-rc28)
+For higher-assurance environments, complete [artifact verification](security.md#verify-release-010-rc29)
 before installation.
 
 ## 2. Create a Restricted namespace
@@ -82,7 +82,7 @@ Download the release-matched Secret structure into a private local file:
 umask 077
 curl --fail --location --silent --show-error \
   --output evaluation-secrets.yaml \
-  https://raw.githubusercontent.com/szymczag/hangar/hangar-v0.1.0-rc.28/charts/hangar/examples/evaluation-secrets.example.yaml
+  https://raw.githubusercontent.com/szymczag/hangar/hangar-v0.1.0-rc.29/charts/hangar/examples/evaluation-secrets.example.yaml
 ```
 
 Replace every `CHANGE_ME` value with a unique, randomly generated credential.
diff --git a/docs/kubernetes/operations.md b/docs/kubernetes/operations.md
index 5f38e7dc9e9..5f7345b8699 100644
--- a/docs/kubernetes/operations.md
+++ b/docs/kubernetes/operations.md
@@ -59,7 +59,10 @@ that one over-limit request returns `429` without creating a job or source.
 
 ## Upgrade a release
 
-### Upgrade from `rc.27` to `rc.28`
+### Upgrade from `rc.27` to `rc.29`
+
+`rc.28` was consumed by an incomplete publication and is not an upgrade target.
+Upgrade directly from the immediately previous complete release, `rc.27`.
 
 This release closes two Todoist import admission gaps. Starting an import now
 requires a server-signed, 15-minute, single-use preview grant bound to the
@@ -79,13 +82,13 @@ Before upgrading:
 
 1. take a PostgreSQL backup, prove that it can be restored in isolation, and
    record the current Helm revision and application image digests;
-2. confirm the target chart is `0.1.0-rc.28`, its application version is
-   `v0.1.0-rc.28`, and its signatures and digests pass the
-   [release verification procedure](security.md#verify-release-010-rc28);
+2. confirm the target chart is `0.1.0-rc.29`, its application version is
+   `v0.1.0-rc.29`, and its signatures and digests pass the
+   [release verification procedure](security.md#verify-release-010-rc29);
 3. render the existing values against the target chart and verify that only the
    expected release versions and immutable image digests change; and
 4. deploy every application image as one coordinated Helm revision. Do not mix
-   `rc.27` and `rc.28` web or API images because their preview-execution request
+   `rc.27` and `rc.29` web or API images because their preview-execution request
    contract intentionally changed together.
 
 Wait for the revision-scoped migration Job to complete before admitting traffic.
@@ -98,7 +101,7 @@ also fail without creating a job or retaining a source object.
 target; the nullable column may remain in the database. It restores the preview
 bypass and duplicate-confirmation race, however, so it is not a
 security-equivalent rollback. Prefer a forward correction and return every
-application component to `rc.28` promptly.
+application component to `rc.29` promptly.
 
 ### Upgrade from `rc.26` to `rc.27`
 
diff --git a/docs/kubernetes/production-install.md b/docs/kubernetes/production-install.md
index e22901e524c..9e22add6881 100644
--- a/docs/kubernetes/production-install.md
+++ b/docs/kubernetes/production-install.md
@@ -5,7 +5,7 @@ stateful services. It is intended for platform engineers participating in
 production qualification and design review.
 
 > [!CAUTION]
-> Hangar `0.1.0-rc.28` is not supported for production. The production profile
+> Hangar `0.1.0-rc.29` is not supported for production. The production profile
 > renders with secure defaults, but it has not completed the installation,
 > upgrade, backup/restore, failure-recovery, security-review, or compatibility
 > gates required for production support. Do not place critical data or users on
@@ -81,7 +81,7 @@ Confirm that:
 ## 4. Create the namespace and TLS Secret
 
 ```bash
-export CHART_VERSION=0.1.0-rc.28
+export CHART_VERSION=0.1.0-rc.29
 export RELEASE_NAME=hangar
 export NAMESPACE=hangar
 export HANGAR_HOST=hangar.example.com
@@ -133,7 +133,7 @@ Download the release-matched example:
 ```bash
 curl --fail --location --silent --show-error \
   --output production-values.yaml \
-  https://raw.githubusercontent.com/szymczag/hangar/hangar-v0.1.0-rc.28/charts/hangar/examples/production-values.yaml
+  https://raw.githubusercontent.com/szymczag/hangar/hangar-v0.1.0-rc.29/charts/hangar/examples/production-values.yaml
 ```
 
 At minimum, set:
diff --git a/docs/kubernetes/security.md b/docs/kubernetes/security.md
index 6bc4c5612a3..067efb5ec7d 100644
--- a/docs/kubernetes/security.md
+++ b/docs/kubernetes/security.md
@@ -1,7 +1,7 @@
 # Kubernetes security and artifact verification
 
 This document explains the chart's security boundaries and provides commands for
-verifying the public `0.1.0-rc.28` release.
+verifying the public `0.1.0-rc.29` release.
 
 ## Security model
 
@@ -88,9 +88,9 @@ that does not enforce policies can fail open.
 
 ## Release trust chain
 
-For `0.1.0-rc.28`, the trust chain is:
+For `0.1.0-rc.29`, the trust chain is:
 
-1. signed Git tag `hangar-v0.1.0-rc.28` identifies the source commit;
+1. signed Git tag `hangar-v0.1.0-rc.29` identifies the source commit;
 2. the release workflow builds AMD64 images with BuildKit SBOM and provenance;
 3. GitHub creates build-provenance attestations;
 4. the workflow signs image and chart digests keylessly with GitHub OIDC;
@@ -101,7 +101,7 @@ For `0.1.0-rc.28`, the trust chain is:
 Verification must use immutable digests and the exact workflow identity. A valid
 signature for a different workflow, repository, tag, or issuer is not sufficient.
 
-## Verify release `0.1.0-rc.28`
+## Verify release `0.1.0-rc.29`
 
 These commands require `curl`, `sha256sum`, GitHub CLI for the GitHub attestation,
 and Cosign for OCI signatures.
@@ -109,8 +109,8 @@ and Cosign for OCI signatures.
 ### 1. Download public release assets
 
 ```bash
-export VERSION=0.1.0-rc.28
-export GIT_TAG=hangar-v0.1.0-rc.28
+export VERSION=0.1.0-rc.29
+export GIT_TAG=hangar-v0.1.0-rc.29
 export RELEASE_URL="https://github.com/szymczag/hangar/releases/download/$GIT_TAG"
 
 mkdir "hangar-$VERSION-release"
@@ -232,7 +232,7 @@ licenses, vulnerabilities, and maintenance status independently.
 
 ## Current limitations
 
-`0.1.0-rc.28` is a prerelease. Only the evaluation profile has completed live
+`0.1.0-rc.29` is a prerelease. Only the evaluation profile has completed live
 cluster qualification. Vulnerability and license approval, production security
 qualification, backup/restore, migration-failure recovery, and the complete
 support matrix remain open gates.
diff --git a/docs/kubernetes/troubleshooting.md b/docs/kubernetes/troubleshooting.md
index 57849339971..f45e5a49b62 100644
--- a/docs/kubernetes/troubleshooting.md
+++ b/docs/kubernetes/troubleshooting.md
@@ -60,7 +60,7 @@ Confirm the chart is public:
 
 ```bash
 helm show chart oci://ghcr.io/szymczag/charts/hangar \
-  --version 0.1.0-rc.28
+  --version 0.1.0-rc.29
 ```
 
 Confirm the node architecture:
@@ -69,7 +69,7 @@ Confirm the node architecture:
 kubectl get nodes --label-columns kubernetes.io/arch
 ```
 
-`0.1.0-rc.28` is AMD64-only. An ARM64-only cluster cannot schedule or run the
+`0.1.0-rc.29` is AMD64-only. An ARM64-only cluster cannot schedule or run the
 qualified images.
 
 Published charts use digest references. Inspect the failed Pod's image without
diff --git a/docs/releases/hangar-v0.1.0-rc.29.md b/docs/releases/hangar-v0.1.0-rc.29.md
new file mode 100644
index 00000000000..2954a77e163
--- /dev/null
+++ b/docs/releases/hangar-v0.1.0-rc.29.md
@@ -0,0 +1,70 @@
+## Security and privacy
+
+`rc.29` hardens the Todoist import review and admission boundary. The execute
+endpoint now requires a short-lived, server-signed preview grant bound to the
+administrator, workspace, destination project, and exact uploaded source. Each
+grant carries a random nonce that can reserve at most one job, so missing,
+expired, altered, cross-scope, and replayed grants fail closed before source
+retention or dispatch.
+
+Import reservation now locks the destination project and rechecks both active
+jobs and completed duplicates inside the reservation transaction. This closes a
+race in which a concurrent import could complete between the earlier request
+check and reservation, bypassing the explicit duplicate confirmation.
+
+The controls were validated with regression tests for mandatory preview,
+actor/project/source binding, expiration, single use, and transactional duplicate
+admission. Publication remains gated on the full API and Todoist suites, security
+migrations, frontend checks, release metadata, Helm policy tests, CodeQL,
+artifact attestations, and keyless signatures.
+
+The publication workflow now retries each keyless image and chart signing
+operation up to three times with bounded backoff. This tolerates transient
+Sigstore timestamp-service connection failures without skipping the mandatory
+post-signature identity verification or overwriting an existing release.
+
+## Migrations and compatibility
+
+Migration `ext.0011_import_job_preview_nonce` adds a nullable unique UUID field
+to import jobs. Existing jobs remain valid and require no data backfill. New jobs
+created through the HTTP Todoist importer consume the nonce from their signed
+preview grant; trusted internal reservation callers receive a generated nonce.
+
+There is no new Helm value, Secret, Kubernetes resource, public route, storage,
+RBAC, or NetworkPolicy change. Existing `rc.27` values and deployment
+configuration remain structurally compatible. The preview grant lifetime
+defaults to 900 seconds and requires no operator action.
+
+Deploy all application images as one Helm revision and wait for the
+revision-scoped migration Job before admitting traffic. The web and API request
+contract changed together: an `rc.29` web client sends the signed grant, while
+the `rc.29` API no longer accepts a client-calculated digest as proof of preview.
+Do not operate mixed `rc.27` and `rc.29` web/API revisions.
+
+The inherited Plane baseline remains final `v1.4.0` at commit `917b23a6`. The
+qualification boundary remains Kubernetes 1.30 through 1.36 (including 1.36.2),
+Helm 4.2, `linux/amd64`, Restricted Pod Security Admission, TLS ingress with
+WebSocket support, a `NetworkPolicy`-enforcing CNI, and persistent storage.
+
+The product version is `v0.1.0-rc.29`, the chart version is
+`0.1.0-rc.29`, the signed Git tag is `hangar-v0.1.0-rc.29`, and the OCI
+chart reference is `ghcr.io/szymczag/charts/hangar:0.1.0-rc.29`.
+`rc.27` is the immediately previous complete publication. `rc.1`, `rc.2`,
+`rc.20`, `rc.24`, `rc.25`, and `rc.28` were consumed by incomplete publication
+attempts and are not upgrade or rollback targets. `rc.24`, `rc.25`, and `rc.28`
+each published only a subset of their containers and no chart or GitHub Release.
+
+## Known limitations and rollback
+
+Hangar `rc.29` remains a prerelease qualified for evaluation rather than
+production. Published images are AMD64-only. The production-profile install,
+backup and restore, migration-failure recovery, vulnerability and license
+approval, and full support matrix remain open qualification gates.
+
+`rc.27` is structurally compatible as an emergency technical rollback target;
+the nullable preview-nonce column can remain in place. Rolling back restores the
+superseded Todoist admission behavior, so there is no security-equivalent
+rollback target. Prefer a forward correction; if availability recovery requires
+rollback, move every application component together, temporarily disable Todoist
+imports, and return to `rc.29` promptly. Restore a database backup only when
+unrelated writes, corruption, or the incident requires point-in-time recovery.