feat(errors): fingerprint v3 grouping with a version-salted hash - #1466

🟢 Confidence 8/10 · likely safe to merge
The risky part — hash rotation, archiving and restore — is pinned end to end by two ClickHouse e2e suites; the 2,148-line v30 snapshot SQL went unread.
_{quality 100/100 · no findings · tests covered · risk high}

Fingerprint v3: version-salted hashes, new frame and message-signature rules, a ClickHouse MV recreation (0039), local schema v30, and restore of archived error issues on recurrence. The MV SQL and its TS mirror apply the same chain, and the parity is pinned by ClickHouse e2e tests.

• FINGERPRINT_VERSION is 3 and 'fp3' is hashed into FingerprintHash, so every issue hash rotates
• Namespaced exception types keep one frame; Effect span and schema key-path lines are not frames
• ERROR_MSG_REDACTIONS cuts ClickHouse query echoes and redacts FS paths, prefixed ids and ULIDs
• The errors tick restores an archived, non-done issue on its next occurrence

Before merge

• Migration · Check it is safe on production data and with the code still deployed · packages/domain/src/clickhouse/migrations/0039_error_fingerprint_v3.ts
• Manual · Warn users before cutover: every open error issue is archived and returns as a new triage issue without assignee, priority, notes or snooze
• Manual · Self-hosted ClickHouse orgs must apply schema migration 0039, or they keep producing v2 hashes that reopen archived issues

_{f68d27e · Updated on every push. Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}