[fxai]

Logging rework

Consistent stdout logging with the service layer as the place for business events.

Changes

• Levels: expected events are no longer logged as ERROR. Failed logins, 403s and invalid tokens are WARNING. Expired tokens and successful logins are INFO. Unexpected errors use exception(), which includes the traceback.
• Audit trail: every write logs one INFO line after the commit, with the acting user, the action and the object (User alice@x deleted activity 'X' (<id>) in assessment <id>). This covers users, assessments, ACLs, activities, groups, assets, tags, files, imports and exports, reports, and seeding (who started it).
• Rejected actions are logged as WARNING: invalid uploads or import files, a blue team user deleting a red team file, attempts to change the main admin.
• Seeding: f-strings replaced by % arguments. A broken single file is a WARNING, a failed import is an ERROR with traceback.
• Frontend: removed the "Logs – Coming Soon" card from the admin page. Logs are not stored in the database.
• Docs: new page Developer Guide → Backend → Logging with the rules, "What is logged" in the admin configuration page, and the roadmap item marked as done.

Notes

• No API or database changes. parse_and_ingest_mitre_data_service has a new optional user parameter.
• Uvicorn's access log is unchanged and keeps its own format.
• All 281 backend tests pass. The docs build passes with --strict.