feat(buglog): one Markdown record per bug, checked against a record standard

The buglog was one 27K-line JSON file whose fields covered only symptom,
root cause and fix, as free text: 2% of entries named the code version a
bug was found on, 12% the build profile, 36% a way to reproduce, and 58% of
the file was OpenWolf hook auto-detections ("Missing guard clause",
"Function not marked async" on .md files).

- .claude/skills/buglog/bug-record.md: the record standard. Eight
  sections (Summary as the title, Description, Environment, Reproduction;
  Root cause, Fix, Verification, References once fixed), each with the
  content it must contain -- e.g. Environment needs the OS, the libc the
  failing binary loads (from its ELF interpreter: glibc 2.42 in the nix
  shell vs 2.40 on the host), toolchain, build profile and commit.
- .wolf/bugs/<id>.md: 500 records migrated from buglog.json; every field
  verified to round-trip. They carry legacy: true and an explicit "not
  recorded" where the old log had no such field; component derived from
  file paths, severity from keywords (else unknown), fix_commits from
  hashes in status_note/fix that git resolves (91 of 463 fixed).
- .wolf/buglog-archive.json: the 710 hook auto-detections, verbatim.
- .wolf/buglog.json is now an index generated from the records, keeping
  the fields OpenWolf's hooks and `openwolf bug search` read.
- scripts/buglog.py rewritten: new (template + Environment collected from
  the machine and --binary), check, status (refuses a status the record
  doesn't support; fixed needs Root cause, Fix, Verification and
  --commit hashes git resolves), note, recur, set, show, list, triage,
  env, index. 29 unittest cases in scripts/tests/test_buglog.py.
- scripts/git-hooks/pre-commit runs `check --staged`: incomplete staged
  records, a legacy record hand-changed to fixed without the fix-time
  sections, a new record claiming legacy: true, or a stale index refuse
  the commit.
- scripts/gitea-sync.py reads the records: issue body = the record's
  sections plus linked fix commits (origin remote, GITEA_COMMIT_REPO to
  override), and a body hash so an issue's text is refreshed when the
  record changes.
- bug-1866 rewritten to the full standard as the worked example.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.wolf/bugs/bug-661.md

@@ -0,0 +1,39 @@
+---
+id: "bug-661"
+status: "fixed"
+status_updated: "2026-09-24"
+status_note: "f139e1c0"
+component: "controller"
+severity: "data-loss"
+timestamp: "2026-06-17T23:30:00Z"
+last_seen: "2026-09-19T09:00:00Z"
+occurrences: 2
+files: ["src/controller/persist.c", "src/controller/commit.c", "src/controller/repl.c"]
+tags: ["controller", "ha", "durability", "fsync", "wal", "commit-engine", "data-loss", "failover", "leader-completeness", "promotion-fence", "async-fsync", "deterministic-repro", "wal-sync-ms"]
+related: ["bug-339", "bug-447", "bug-396"]
+fix_commits: ["f139e1c0"]
+legacy: true
+---
+
+# bug-661: 3-node failover test lost committed jobs: 7 earliest JobIds (WAL LSN<=20), majority-ACKed and…
+
+## Description
+3-node failover test lost committed jobs: 7 earliest JobIds (WAL LSN<=20), majority-ACKed and survived first failover, permanently gone after a restarted node with near-empty WAL won election. joblist dropped from 10 to 3.
+
+## Environment
+_Not recorded (migrated from buglog.json)._
+
+## Reproduction
+_Not recorded (migrated from buglog.json)._
+
+## Root cause
+'committed' does not imply 'durable'. WAL fsync is asynchronous (persist.c:173 fsync_worker, timer wal_sync_ms); persist_append and the standby WalAck path do NOT fdatasync before ACK. commit_on_ack (commit.c:303) advances committed_lsn on majority ACK = OS page cache only, durable on zero disks. On kill+restart, killed nodes lose the not-yet-fsynced tail; persist_recover hits CRC break at zeroed region (prev_crc=00000000, offset 40) and truncates replay to ~0 entries, yet the hollow node stays eligible, wins election under degraded required=1 quorum (PreVote+freshness gate cannot fence it because the committed entries were durable on nobody), self-promotes advertising committed_lsn=21 over an empty job table, and the node holding the real data converges DOWN. Violates Leader-Completeness assumption (majority-ACK != durable-on-majority) in src/controller/CLAUDE.md.
+
+## Fix
+NOT YET FIXED. Discovery -> new spec ha-commit-durability (Path C, brief written). R1 fsync-before-ACK (standby fdatasync before WalAck, primary self-count only after local fdatasync, committed_lsn advances only on durable majority, group-commit to bound latency). R2 promotion fence (WAL CRC/replay failure => ineligible to lead until caught up, FATAL not silent truncate; never lead below known committed high-water even under degraded quorum). Live E2E reproduces via xce_test jobsub + primary kills on /xce-deploy-ha. DETERMINISTIC REPRO (task 1.3, 2026-06-18): `bash src/tools/test-commit-durability.sh --deterministic` launches the cluster with --wal-sync-ms 30000 (plumbed via deploy-ha.sh start.sh `$*` passthrough, EXTRA_CTRL_ARGS) so the primary's fsync_worker never fires in-window -> every committed entry is page-cache-only on the primary (majority_candidate_locked counts cap=highest_appended_lsn=current_lsn-1, NOT durable). It then drives rolling PRIMARY kills (each right after committing to that primary) + restart, so hollow nodes re-lead. RED CONFIRMED: 6-round run lost the 3 EARLIEST committed JobIds permanently (rounds 4 and 6 + final check), Results 5 passed/3 failed, exit=1 — matching the incident signature (earliest jobs gone). NOTE: a single double-kill does NOT repro — this codebase enforces strict majority (lone survivor will NOT self-elect: log shows 'no single-voter primary within 40s'); loss needs the ROLLING/term-accumulating path the incident used. Evidence log: dur-det-run.log in worktree.
+
+## Verification
+_Not recorded (migrated from buglog.json)._
+
+## References
+- Related: bug-339, bug-447, bug-396