feat: add retrospective intelligence to create-story workflow

Load all retrospective files during story creation to carry forward
lessons learned, open action items, architecture corrections, and
deferred code review items. Fulfills Epic 2 retro action item A1.

Also includes Epic 2 retrospective and sprint status updates.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

_bmad-output/implementation-artifacts/sprint-status.yaml

@@ -34,7 +34,7 @@
 # - Dev moves story to 'review', then runs code-review (fresh context, different LLM recommended)
 
 generated: 2026-03-11
-last_updated: 2026-03-22T00:00:00
+last_updated: 2026-03-24T00:00:00
 project: "l'ami fiduciaire"
 project_key: NOKEY
 tracking_system: file-system
@@ -66,7 +66,7 @@ development_status:
   2-2-priority-alerts-panel: done
   2-3-worker-scoped-dashboard: done
   2-4-dashboard-activity-feed: done
-  epic-2-retrospective: optional
+  epic-2-retrospective: done
 
   # Epic 3: Collaboration, Nudge System & Notifications
   epic-3: backlog