rainix-tag-release invokes rain.deploy's cutRelease() instead of reimplementing the freeze

.github/workflows/rainix-tag-release.yaml

@@ -56,9 +56,10 @@ on:
         default: sol-v
       snapshot-generate-cmd:
         description: >-
-          Command that regenerates the deploy-pin snapshot from the (deterministic) bytecode into src/generated/<tag>/, DEPLOY_TAG and any pointer libs, then formats. Run after [package].version is set to the release version, so the generated tag matches it. e.g. `forge script ./script/BuildPointers.sol && forge fmt`.
-        required: true
+          Command that cuts the release: it regenerates the rolling `src/generated/candidate/` pins from the current source and freezes a copy of them as `src/generated/<tag>/`, in that order and in one call, then formats. `BuildScript.cutRelease()` is that call, so the default is the whole of it for a deploy repo whose `script/Build.sol` extends `BuildScript` and such a repo passes nothing. Run after `[package].version` is set to the release version, so the tag the freeze derives from it is the one being released.
+        required: false
         type: string
+        default: 'forge script ./script/Build.sol --sig "cutRelease()" && forge fmt'
       test-cmd:
         description: >-
           Pre-publish verification gate. Run against the regenerated snapshot; for a deploy repo this is the fork suite that reads the live chain and asserts it matches the fresh pins, so a release that snapshots addresses the chain does not actually carry fails loud BEFORE publishing. Default `forge test`.
@@ -196,11 +197,24 @@ jobs:
             echo "::error::foundry.toml has no [package] version line to set to ${VERSION}" >&2
             exit 1
           }
-      - name: Regenerate the deploy-pin snapshot
-        # Deterministic: the pins are computed from bytecode (address = f(bytecode)
-        # under CREATE2), so this needs no chain access and produces the exact
-        # src/generated/<tag>/ the release publishes and commits.
-        run: nix develop github:rainlanguage/rainix/${{ env.RAINIX_SHA }}#sol-shell -c bash -c '${{ inputs.snapshot-generate-cmd }}'
+      - name: Cut the release snapshot
+        # One call regenerates the rolling src/generated/candidate/ pins and
+        # freezes a copy of them as src/generated/<tag>/, so there is no point
+        # between the two at which the record and the pins the release publishes
+        # can disagree. Deterministic: the pins are computed from bytecode
+        # (address = f(bytecode) under CREATE2), so this needs no chain access and
+        # produces the exact snapshot the release publishes and commits. The
+        # ordering, the version read, the append-only refusal and the guards
+        # around them all live in that call — LibRainDeploySnapshot.freeze, via
+        # BuildScript.cutRelease().
+        env:
+          # Via env, not interpolated into the script body: a workflow input
+          # spliced into `run:` text is a template-injection surface. The
+          # expansion is one word, which bash then reads as the script.
+          SNAPSHOT_GENERATE_CMD: ${{ inputs.snapshot-generate-cmd }}
+        # `set -euo pipefail` so a command written as `a; b` cannot hide a's
+        # failure behind b's success.
+        run: nix develop github:rainlanguage/rainix/${{ env.RAINIX_SHA }}#sol-shell -c bash -c "set -euo pipefail; $SNAPSHOT_GENERATE_CMD"
       - name: Commit the release snapshot
         # Commit BEFORE the append-only gate and Soldeer push so both operate on a
         # clean, inspectable tree. The commit is what lands on main below.