chore(observability): align the AI service log format with the web/worker logs

[Fluory]

Ziel

One log format across web, worker and AI service so a log shipper can parse and correlate all three without per-service rules. Today web/worker log pino JSON (time, lower-case level labels such as "info", fixed key whitelist – #28 / PR #45) while the AI service logs ts and upper-case levels.

Akzeptanzkriterien

• AI service log lines use the same keys as logEvent: time (ISO 8601), level (lower-case label), event, and correlation keys requestId, jobId, companyId where known.
• The AI service keeps its privacy guarantee: no document content, quotes, names or e-mail addresses in logs (existing tests keep passing; one test asserts the new key set).
• docs/technical/operations.md documents the shared format once.

Nicht Teil dieser Aufgabe

• Log shipping, alerting, dashboards.

Betroffene Bereiche

• services/ai/src/requestflow_ai/ (logging setup), services/ai/tests/, docs/technical/operations.md

Testplan

Kriterium	Prüfart
Shared key set + format	pytest capturing a log line
No content in logs	existing privacy tests + new assertion

Security/Privacy betroffen?

Logs are a data-leak path – keep the whitelist approach; no request bodies.

Found in the security review of PR #45.

[Fluory]

Claimed by @Fluory (Claude Code session) on branch claude/chore-ai-log-format-51. Draft PR follows.

---

Generated by Claude Code