feat(core): authz grants cache — #11633 leg B: coarse invalidation, default off, expiry-boundary rule, bypass list - #13415

Fixes #11971

Leg B of the accepted #11633 cross-request caching design (maintainer acceptance 2026-08-25, verbatim 「接受你的建议，继续」), built on the #11968 substrate (PR #12652). Clause-②: yes (authorization answers) — this PR is opened as a draft and parked for a CONTRACT_REVIEW_TIER reviewer; that is the expected outcome. The needs:contract-review re-attach now that a reviewable diff exists is left to the seat that owns that mechanism (per the 2026-08-28 #12887 ruling quoted on the card).

What ships

resolveUserAuthzGrants (packages/core) can cache its resolved envelope across requests, governed by OS_AUTHZ_GRANTS_CACHE_TTL_MS.

• Fork 4 — default 0, cache OFF, off is a real path. With the shipped default the open call returns undefined with zero side effects: no engine middleware, no epoch subscription, no entry — pinned by asserting the engine double's middleware count and epoch listener count are both zero and the second resolution re-issues the identical query multiset.
• Fork 1A — coarse invalidation, two seams. (1) A cache-owned engine middleware retires everything on any write to the watched set (sys_member, sys_user_position, sys_user_permission_set, sys_position, sys_position_permission_set, sys_permission_set, sys_user), bumping AFTER the write completes so an in-flight resolution stamps a pre-write generation and dies on arrival. (2) An engine write-epoch subscription retires wholesale on every non-write reason: metadata (a permission set can be DECLARED — plugin-security bumps the engine epoch for it), remote (peer hints carry no object; wholesale is the payload's stated contract), manual. The raw epoch alone is deliberately NOT consumed for local writes — it advances on writes to every object, which would revive the measured sys_session trap.
• The ruled keying traps hold. sys_session stays out of the watched set — pinned with a control showing the session-activity write DID advance the engine epoch while the cache survived. A sys_member write retires the organization's entries (coarse retires everything, which contains the ruled behaviour) — pinned as: user X's org_user_ids changes when user Y's row is written.
• Expiry-boundary rule. Entries expire at min(ttl, nextBoundary); nextGrantValidityBoundary (new, in grant-validity.ts, sharing isGrantActive's parser) scans exactly the rows the validity predicate was applied to — including currently-inactive rows, because a future valid_from is a flip the timer must catch too. Pinned in both directions with an injected clock and a one-hour TTL.
• TTL is the correctness contract. The bus only narrows: pinned by a two-node pair with a bridge double (one hop, no clock advance) and without one (stale inside the TTL — the accepted window — and converged past it with no message ever delivered).
• Ruled bypass list, re-derived by symbol (both files had moved off the ruling's line numbers): plugin-security/src/explain-engine.ts buildContextForUser (now line 473→481 region) and service-automation/src/plugin.ts setUserGrantsResolver (was :812, now :869 region) pass bypassGrantsCache: true with the ruling's reason preserved in comments. Bypass reads nothing from and writes nothing into the cache — both halves pinned.
• Docs + changeset: the canonical env-vars table row drops its "no cache reads this value yet" caveat; changeset = core minor, plugin-security/service-automation patch.

One measured deviation from the design's lean (not from the ruling)

Design §4 B.2 leans toward caching the seedless envelope and re-applying seeds outside, conditioned on seeding being "a pure prepend, which must be pinned, not assumed". Measured before implementing: it is not a pure prepend. Seeds flow into derivations — a seed named in ORGANIZATION_ADMIN_GRANTS moves the ADR-0095 posture rung, and seeded email/ai_seat suppress the sys_user read (needsUserRow), so a seedless resolution issues a query the seeded path must not issue. Re-deriving those outside the resolver would be a second copy of authorization logic — the #10348 drift shape. So seeds are part of the cache key (the design's other named option), which keeps every cached answer bit-identical to its own uncached resolution by construction. Pin 5 carries the isolation, ordering, and suppressed-read halves.

Test plan (design §7: pins 1–7, 9 + the required ablation)

New suite packages/core/src/security/resolve-user-grants-cache.test.ts (28 tests) + pin 6 in plugin-security/src/explain-engine.test.ts. The batch-equivalence harness (recording double + 11-fixture matrix) moved to resolve-authz-context.batch-equivalence.testkit.ts so the identity pins reuse the fixtures without re-registering that suite; the goldens stay in the test file. The seam double's write verbs open with assertEngineUpdateDispatch/assertEngineDeleteDispatch (metadata-core — the non-cycle edge) and the RETAINED ledger records it.

• Pin 1: identity over all 11 fixtures — cached deep-equals uncached including array order, AND the hit issues zero reads. Plus clone isolation (a caller mutating its answer cannot poison the next).
• Pin 2: revoke and grant through the engine observed by the next resolution, no clock advance, TTL one hour — asserting the capability/posture at the end of the chain, never "the cache was cleared".
• Pin 3: validity boundary, both directions, no write anywhere.
• Pin 4: peer membership (B.3). Pin 5: seed isolation (B.2). Pin 6: explainer observes a revocation the cache provably still holds (control asserts the cached path IS stale first). Pin 7: zero-means-off (above). Pin 9: two-node bus/TTL pair.
• Decline rule: a ql without the seams resolves uncached every time (never degrades to TTL-only).

⭐ Ablation of write-invalidation (required by the ruling) — invalidation is load-bearing

Declared direction before running: with both gen-bump seams removed and only the TTL/boundary expiry left, the read-after-write pins go RED; boundary/TTL/identity pins stay GREEN.

• Mutation: both state.gen += 1; sites in resolve-user-grants-cache.ts replaced with a no-op marker. Proven on disk before reading any result: marker grep = 2, original-text grep = 0, git hash-object = 5257ceb... vs HEAD blob 8a3875a....
• No rebuild needed for the ablated legs, and that was verified rather than assumed: the pins import the cache module by in-package relative path, so vitest resolves the mutated source directly (no dist in the resolution path; the RED result itself confirms the mutated code ran).
• Result, exactly as declared — 5 RED / 23 GREEN: revoke-through-engine RED, grant-through-engine RED, metadata/manual retirement RED, peer-membership RED, bus-hop RED; TTL convergence, validity boundary, identity, off-path all GREEN.
• Restore proven by state, not exit code: git checkout HEAD -- $ABS_PATH (absolute path, trap on EXIT/INT/TERM), then git diff HEAD empty, git status clean, blob hash back to 8a3875a..., marker grep 0; rerun 28/28 green. Cycle run twice — once at the feature commit, once at the final head ae0ec14b6.

Verification (all at final head ae0ec14b6 unless noted)

• Gate family derived at edit time (scripts/pm/dispatch-gates.mjs --repo objectstack-ai/objectstack, derivation stamped at ae0ec14b6 after merging origin/main): 39 commands. 38 green. check:dual-build-cjs-loads exits 3 = NOT MEASURED (its own text: prerequisite not met, full workspace dist required — CI runs it after the full build). check:skill-examples initially exited 1 for the same prerequisite class (client dists not built); after turbo run build --filter=@objectstack/client-react... it is a real green: "260 prose examples type-check across 3 surfaces".
• check:engine-double-contract (self-derived, not in the path-derived list): initially red on the new double, fixed by pinning to the producer predicates + --write ledger row; final run green ("653 (file, verb) rows held by the RETAINED ledger").
• Full-repo pnpm lint (eslint . --no-inline-config): exit 0 (at merge commit 0f348d3a4; the two commits after it touch one test file + the ledger json, both relinted green in the final union's lint-family gates).
• Suites: core 44 files / 1088 tests green at ae0ec14b6; plugin-security 89 files / 1637 tests green and its three-program typecheck green with the new test file confirmed IN the tsc program via --listFiles (zero-residue regime of PR test(plugin-security): compile the 89 test files no tsc program read #13395 — nothing parked); service-automation 91 files / 1091 tests green (at 0f348d3a4; untouched since). check:nul-bytes green.
• bypassGrantsCache verified present in core's built dist/index.d.ts (plugin-security resolves core unaliased, per the KNOWN_UNALIASED_TEST_IMPORTS ledger), and service-automation/src/plugin.ts compiles clean against it (0 tsc errors in that file; the package's pre-existing test-file noise is environmental and untouched).

Serial fences respected

No touches to permission-set-projection.ts / packaged-permission-set-restore-leg.test.ts (card #12020), none of PR #13371's eight files (service-automation/src/plugin.ts is not among them), no service-datasource/runtime manifests (card #12943 — its optional-peers change arrived via the origin/main merge, untouched), no plugin-sharing/plugin-auth (PR #13397). No skills/**, no content/docs/releases/**, no pm:* label or assignee changes.

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