[congvc-bot-x99]

Status: Ready for Cheese's review and merge. Fresh current-target CI: PASS. Repair for the duplicate migration prefix 627 on main. main now holds three 627 migrations. Current base 5a0ad9516afbdd143a2ba7361602ccf1dec535a0, head e52d3a3b20afbf3bff72ba58356c9b742accee8c. It blocks CHE-1727 PR #254 CI. It is not a change to wakeups.

Conditions:

• Only Cheese merges. No deploy. No production migration was run. PR feat(wakeups): workspace-wide switch to pause wakeup firing (CHE-1727) [squash] #254 stays draft until verified repair merge and its required fresh final-pair verification.
• Independent source review: PASS, no P0/P1 findings, signed by x99-codex-luna (gpt-6-luna, Codex/OpenAI), independent of author x99-claude-sonnet (Anthropic). Comment 01a1453a-8793-7aaa-b787-b6e866fc1638 on CHE-1824 covers this exact base/head. Its OCR receipt passes the pinned schema checker. Native selection and direct review cover all 15 raw-tree paths through two previews: 9 selected and 6 excluded. The range preview uses merge base a736250c26b9ba25cef9e0c13af6bc7ee1e7aa19; the separate intervening-main preview completes coverage. It is not one raw-range OCR selection. A changed base/head requires fresh applicable verification.
• Historical test-first gate: WAIVED for head e52d3a3b20afbf3bff72ba58356c9b742accee8c only by Cheese comment 01a144d7-04c1-7f15-82eb-f545479c6953. Original behavioral-red evidence remains NOT-RUN, not PASS. The first commit of this PR (96d1464b5) mixed the compatibility test, the README and the rename. The unchanged uniqueness test failed on main: https://github.com/cheese-work/multica/actions/runs/38854767783. The history is not rebuilt. New tests added later do not clear that gap. No other check or merge gate is waived.
• Later current-main correction: retrospective tests-only commit bc2dc1fbc precedes the fix commit e52d3a3b2.
• A separate script-checks failure on main (a Helm download, run https://github.com/cheese-work/multica/actions/runs/38877201171) is not part of this PR. A migration fix alone is not an all-main CI PASS.

Change:

• Only one of the three keeps 627. 627_notification_channel_preference stays: 628_notification_channel_preference_index builds an index on its table, so it must run before 628.
• 627_agent_task_queue_context becomes 630_agent_task_queue_context (unchanged from the earlier push).
• 627_unpin_archived_chat_sessions becomes 653_unpin_archived_chat_sessions. Up and down SQL bytes are identical (sha256 of up 8ae4bf08..., of down d7d8808e...).
• Free-number check on 2026-10-16 across all open PRs: 627 to 632 (feat(wakeups): L9 scoped-event outbox capture and drain (CHE-1199) [squash] #172), 640 to 646 (feat(wakeups): L10 custom event and condition rules with activation sweep (CHE-1200) [squash] #173), 628 (feat(chat): deliver held decision groups atomically (CHE-1750) [merge] #260, feat(runtime): reservation schema with representable effects (CHE-1740) [squash] #288), 629 and 630 (feat(chat): auto-compact a web DM at the context threshold (CHE-1807) [merge] #285), 650 to 652 (feat(chat): create a coalesced inbox record for DM replies (CHE-1793) [squash] #276). Base main holds 626 to 629. The repair candidate adds the renamed 630. 653 is the next free number.
• Ledger compatibility: versions are file basenames. The runner applies every file whose version is not in schema_migrations, in sorted order, and does not compare against the highest applied number. A database that applied an old name runs the same idempotent SQL again under the new name and keeps its old row. The context migration is ADD COLUMN IF NOT EXISTS. The unpin migration is one UPDATE that clears pins on archived rows, which handlers already keep clear. server/cmd/migrate/README.md documents this.
• The uniqueness test is not weakened or skipped. No allowlist entry was added.

Evidence:

• Red on the merged tree, before the fix commit: TestMigrationNumericPrefixesAreUnique fails with migrations 627_notification_channel_preference and 627_unpin_archived_chat_sessions share numeric prefix 627. The new test TestUnpinArchivedChatSessionsRenumberKeepsTheData fails at bc2dc1fbc because 653_unpin_archived_chat_sessions.up.sql does not exist. That second failure is a missing-file failure, not behavioral-red evidence.
• Green at e52d3a3b2, on a task-owned pgvector/pgvector:pg17 container (DSN verified as loopback, not 5432): go test ./internal/migrations passes. go test ./cmd/migrate passes in full (53 s), including both renumber tests, each for a fresh and a previously applied database, run twice. go run ./cmd/migrate up on an empty database applies 627, 628, 629, 630 and 653 in order, and a second run skips them. go vet is clean. golangci-lint run --new-from-merge-base=origin/main reports 0 issues.
• Fresh current-target CI: PASS, https://github.com/cheese-work/multica/actions/runs/38932599920. All 11 non-skipped jobs succeeded, including backend-tests, backend-agent-tests and the backend aggregate. GitHub skipped the remaining 7 jobs. None failed or remain pending. The separate Changelog line check also passes. Closing and reopening the draft PR refreshed the recorded base without changing its head or commits. GitHub merge candidate b69eaf6b45c1405b770cda0010c425fdf8c023a9 has this exact base/head as parents and tree e79b04ab5f1681d096f6616383ab54eae8dc8702.
• Local CI-equivalent integration: commit 7eb28c6dbab1512d79f349567e9343b43a63a6b9 has the same parents and tree as the GitHub candidate. Race build, tagged vet, migrations, lifecycle checks, sqlc, vulnerability scan and lint pass. The regular and agent suites FAIL on X99. Matching pristine-main controls fail in execenv, governance/receipt and the Codex deadline test. Wecom fails intermittently on both trees. These local suite results remain FAIL, not green, and do not substitute for GitHub CI. The earlier CLI-package path artifact disappears outside the Multica workdir. All database services were task-owned and removed. No shared or production database access occurred.

Writing lint: the three passive-voice warnings are true positives retained for negative restrictions. The semicolon warning is a true positive retained for OCR-scope separation. The long-sentence warning is a true positive retained for migration-number reservations. The synonym warning is a false positive because "fix commit" identifies the implementation commit.

Changelog: none

Closes CHE-1824

[congvc-bot-x99]

Cross-link: #289 (an alternative 628 rename) is closed without merging. This PR is the sole repair lane. #285 (A3) merges this head 96d1464b556fa1f32518e90e54495a6c3c52dcbf unchanged and keeps its own compaction migration 629.