NCE-28 NCE-29: improve Audit Log context and health-check behavior

[FortPT]

Implements NCE-28 and NCE-29 on top of the validated NCE-21/NCE-27 changes.

• Audit entries now expose the authenticated username when available.
• Audit Log shows action, user, affected resource/resource ID, outcome, and safe details.
• Audit search includes actor and resource context.
• Workspace loading no longer automatically runs platform health checks.
• Health checks remain available through the explicit Run checks action.

Validation:

• 50 focused platform/WebUI/routing tests passed.
• Python compile check passed.
• app.js and qa_patch.js syntax checks passed.
• git diff --check passed.

Keep draft until Development validation completes.