refactor(storage): split structured mutation modules

[Jurij89]

Summary

• Split the bounded structured-mutation implementation into focused delete, retention, subject replacement, graph projection, projection copy, and shared primitive modules.
• Keep one optional TripleStore.structuredMutation() capability, one closed public descriptor union, and the existing compatibility facade; adapters and callers do not gain another probing/forwarding protocol.
• Preserve validation order, SPARQL bytes, byte/operand bounds, graph accounting, quad rewriting, worker RPC descriptors, and immutable effect capture.
• Reduce bounded-structured-mutation.ts from the operation grab bag to a small exhaustive dispatcher and compatibility/export boundary.

Related

• Fixes refactor(storage): split bounded structured mutations into focused capabilities #2190
• Part of Reconnect-triggered background sync amplification can starve foreground catch-up #2052
• Stacked on merged PR refactor(storage): own structured mutation commit effects #2194, which fixes refactor(storage): keep structured mutation effects behind storage ownership #2188
• Builds on security(storage): close leased raw SPARQL mutation routes #2187 and refactor(storage): migrate exact managed mutations #2185
• Execution plan: agent-docs/plans/2026-08-09-system-record-followup-refactors.md

Diagrams

• No observable flow changes. The PR only decomposes the existing internal structured-mutation implementation; callers, adapter dispatch, generated SPARQL, effects, and store behavior remain unchanged.

Files changed

File	What
packages/storage/src/bounded-structured-mutation.ts	Exhaustive facade, dispatcher, quad rewrite, graph/effect model, and compatibility exports.
packages/storage/src/structured-mutation/primitives.ts	Shared safe IRI/string/list validation and operand/serialized byte budgets.
packages/storage/src/structured-mutation/delete-subjects.ts	Explicit subject-set delete validation and SPARQL.
packages/storage/src/structured-mutation/retention.ts	Ranked-subject and linked-record retention operations.
packages/storage/src/structured-mutation/replace-subject-predicates.ts	Predicate-scoped atomic replacement and object-rewrite preflight.
packages/storage/src/structured-mutation/replace-projection-from-graph.ts	Staging-to-target projection replacement.
packages/storage/src/structured-mutation/copy-subject-projection.ts	Bounded exact-root projection copy and ordered chunk planning.

Test plan

• Storage build after restacking on refactor(storage): own structured mutation commit effects #2194
• bounded-structured-mutation.test.ts: 19 passed, including all six real worker-RPC variants
• external-literal-store.test.ts: 12 passed
• graph-set-index-store.test.ts: 43 passed
• changelog-store.test.ts: 42 passed
• Focused total: 116 passed
• Existing validation/error fixtures pass unchanged
• Existing graph-index and changelog accounting suites pass unchanged
• git diff --check; worktree clean

[otReviewAgent]

Review Agent completed this review and found no issues.

[Jurij89]

@otReviewAgent Please run a convergence review against current head 84facbf; the latest automated no-issues review predates the final follow-up commit. CI is green and there are no unresolved threads.

[Jurij89]

@otReviewAgent Please review the current head for convergence. The branch has green CI and no unresolved threads; this request is specifically for the latest head after the storage split follow-up updates.

[Jurij89]

@otReviewAgent Please review the current head after the empty retrigger commit; CI and all prior threads should be evaluated against that head.