feat(rbac): complete HTTP endpoint integration + role configs

HTTP Endpoints with RBAC:
- ingest_handler: project-level write access check
- learn_handler: project-level write access check
- projects_handler: filter returned projects by user access
- query_handler: filter search results by resource access
- context_handler: project-level read access check

Example Role Configurations (config/roles/):
- admin.yaml: full access to all resources
- portfolio-agent.yaml: public visitor access
- authenticated-user.yaml: logged-in user access
- homelab-team.yaml: team-scoped project access

All 660+ tests passing.

config/roles/admin.yaml

@@ -0,0 +1,8 @@
+# Admin role: full access to all resources
+name: admin
+description: Full administrative access to all resources
+
+rules:
+  - resources: ["*"]
+    verbs: [read, write, delete, query]
+    # No scope restrictions - access everything