Stability checkpoint — Dashboard B-6b complete (3 widgets extracted)

Single MR landed since stable-v1.0.39 (UI !108 → 0f0192f) :

♻️  Refactoring
- B-6b dashboard widget split (1 widget per file pattern). Parent
  dashboard.component shrinks 745→670 .ts and 505→179 .html (-65%
  template). 3 standalone widgets extracted :
  - DashboardHealthProbes (130 LOC) — 3 cards health/readiness/liveness
  - DashboardQualitySummary (151 LOC) — 4 cards /actuator/quality
  - DashboardArchitectureMap (149 ts + 175 html) — topology + Docker controls
  Each widget < 175 LOC, fully self-contained with signal inputs +
  event outputs.

📚 Type cleanup
- New shared interfaces in dashboard-types.ts so widgets reuse parent
  signal types without duplication : QualitySummary, EnrichedDockerContainer.

Post-merge main pipeline #407 green on SHA 0f0192f.