feat: persistent rotating logs + live Logs UI

[roziscoding]

Adds durable log storage the UI can read, per the design we settled on: an in-process rotating NDJSON file (no external logrotate, no worker threads) plus a management API the Nuxt UI consumes for backfill + a live SSE tail. Pitchfork/supervisor is intentionally not part of this — deferred to a later change.

Backend

logger.ts now fans everything through one in-process pino multistream:

pino ─ multistream ─┬─ console (stdout in prod; pino-pretty as an in-process stream in dev)
                    ├─ otel bridge (when tracing on, unchanged)
                    ├─ RotatingFileSink → /config/logs/jack.ndjson   (persistence + retention)
                    └─ LogHub → live SSE fan-out

• RotatingFileSink — a ~90-line native sink (node:fs, synchronous). Rotates before the overflowing write so every file stays within maxBytes; renames jack.ndjson → .1, shifts .N up, prunes past maxFiles. No dependency (your call), stable active-file path.
• LogHub — doubles as a multistream destination: parses each line and pushes it to live SSE subscribers, and serves backfill() (last N lines) from the persisted file. Live delivery taps the log pipe directly, so it's oblivious to rotation — no file-tailing/reopen dance.
• Persistence is free: logs default to dirname(APP_CONFIG_PATH)/logs = /config/logs, the same mounted volume as the sqlite DB. No Dockerfile/compose change. New env (all defaulted): LOG_TO_FILE, LOG_DIR, LOG_MAX_FILE_BYTES (10 MiB), LOG_MAX_FILES (5).
• Management API (key-guarded): GET /logs?lines=N&level= (backfill) and GET /logs/stream (SSE live tail).

Redaction already runs in pino's log formatter, so the file/hub receive pre-scrubbed lines.

Note: the module dir is modules/logging/ (not logs/) because .gitignore has a bare logs rule that would have swallowed the source.

UI

New Logs page (+ nav entry): backfills the last 500 lines, then live-tails via EventSource through the existing BFF proxy. Level filter (reloads backfill + reconnects), pause/resume, clear, click-to-expand row detail, stick-to-bottom auto-scroll.

Verification

• Backend: full suite 411 pass / 0 fail; typecheck + eslint clean. New unit tests cover rotation/pruning, hub pub-sub + backfill (level filter, malformed lines), and the router (backfill route + a real SSE stream test). Plus an end-to-end smoke run: the real production logger writes the file, GET /logs?level=warn returns exactly the warn+error lines, no-key → 401, /logs/stream → text/event-stream.
• UI: nuxt typecheck clean, eslint clean, and a full production nuxt build succeeds (SFC compiles/bundles).
• Not yet done: no visual/browser screenshot — there's no local management mock in this checkout to run the UI against, and SSE-through-the-BFF is best eyeballed against the real API. Worth a quick look when you're back; the proxy already returns res.body as a stream for every GET, so the live tail should pass through unchanged.

Requires the gitignored generated schema types (bun run generate in packages/schemas) for typecheck — unchanged from current CI expectations.

Greptile Summary

This PR adds persistent log storage and a live Logs page. The main changes are:

• Rotating NDJSON log files for backend logs.
• Management API endpoints for log backfill and live SSE streaming.
• Nuxt Logs UI with filtering, pause/resume, clearing, and row details.
• Follow-up fixes for file-sink startup failure, rotated backfill, level filtering, and stream reload races.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

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