NextGraph integration (WIP), broker banner, and feature-based architecture

- Add NextGraph data layer with @ng-org/orm, SHEX shapes (Event, UserProfile,
  Participation), session management, and FestipodDataContext with dual-mode
  operation (connected via NextGraph or local seed data)
- Add BrokerBanner and NgStatus components showing connection status
- Refactor to feature-based architecture: organize code by business domain
  (event, user, home, auth, workshop, meeting, notification) instead of
  technical layer. Modules only import from shared/, never from each other
- Collocate BDD features and step definitions with their modules: event-specific
  steps in event/steps/, user steps in user/steps/, shared generic steps remain
  in shared/steps/
- Set up multi-layer BDD structure (frontend/backend/e2e steps per module)
- Add project documentation (AGENTS.md, .project/knowledge/)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cucumber.json

@@ -1,10 +1,11 @@
 {
   "default": {
     "import": [
-      "features/support/**/*.ts",
-      "features/step_definitions/**/*.ts"
+      "src/shared/support/**/*.ts",
+      "src/shared/steps/**/*.ts",
+      "src/modules/*/steps/**/*.ts"
     ],
-    "paths": ["features/**/*.feature"],
+    "paths": ["src/modules/*/features/**/*.feature"],
     "format": [
       "progress-bar",
       "json:reports/cucumber-report.json",