feat: camera apply-changes flow + secret-safe source_config patch UX

[lan17]

Summary

• add apply_changes support to camera mutation endpoints so create/update/delete can request runtime reload in the same API call
• extend camera mutation response payload with runtime_reload details when reload is requested and accepted
• keep canonical API failure behavior for reload conflicts and runtime config errors
• add a source-config patch editor in the cameras UI (JSON patch input, explicit null clears, no redacted placeholder round-trip)
• improve camera action UX with clearer mutation error feedback and reload status refresh behavior

API Changes

• POST /api/v1/cameras?apply_changes=true|false
• PATCH /api/v1/cameras/{name}?apply_changes=true|false
• DELETE /api/v1/cameras/{name}?apply_changes=true|false
• ConfigChangeResponse now optionally includes:
  • runtime_reload: { accepted, message, target_generation }

UI Changes

• add CameraSourceConfigEditor for partial source-config updates
• wire applyChanges through create/update/delete camera mutations
• surface explicit mutation failure messages in camera actions
• keep restart-required banner semantics consistent with immediate apply mode

Tests

• backend: expanded behavioral API route coverage for camera apply-changes and secret-safe patch flows
• UI: added/updated behavioral tests for camera actions and source-config editing flows

Validated locally with:

• make check (ruff, mypy, backend pytest + coverage, ui check)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.01%. Comparing base (9279134) to head (6713258).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #27      +/-   ##
==========================================
+ Coverage   81.96%   82.01%   +0.04%     
==========================================
  Files          94       94              
  Lines        8158     8177      +19     
==========================================
+ Hits         6687     6706      +19     
  Misses       1471     1471              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.