feat: migrate UI to @cameleer/design-system, add backend endpoints

Backend:
- Add agent_events table (V5) and lifecycle event recording
- Add route catalog endpoint (GET /routes/catalog)
- Add route metrics endpoint (GET /routes/metrics)
- Add agent events endpoint (GET /agents/events-log)
- Enrich AgentInstanceResponse with tps, errorRate, activeRoutes, uptimeSeconds
- Add TimescaleDB retention/compression policies (V6)

Frontend:
- Replace custom Mission Control UI with @cameleer/design-system components
- Rebuild all pages: Dashboard, ExchangeDetail, RoutesMetrics, AgentHealth,
  AgentInstance, RBAC, AuditLog, OIDC, DatabaseAdmin, OpenSearchAdmin, Swagger
- New LayoutShell with design system AppShell, Sidebar, TopBar, CommandPalette
- Consume design system from Gitea npm registry (@cameleer/design-system@0.0.1)
- Add .npmrc for scoped registry, update Dockerfile with REGISTRY_TOKEN arg

CI:
- Pass REGISTRY_TOKEN build-arg to UI Docker build step

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

cameleer3-server-app/src/main/resources/db/migration/V5__agent_events.sql

@@ -0,0 +1,13 @@
+-- Agent lifecycle events for tracking registration, state transitions, etc.
+CREATE TABLE agent_events (
+    id         BIGSERIAL    PRIMARY KEY,
+    agent_id   TEXT         NOT NULL,
+    app_id     TEXT         NOT NULL,
+    event_type TEXT         NOT NULL,
+    detail     TEXT,
+    timestamp  TIMESTAMPTZ  NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_agent_events_agent ON agent_events(agent_id, timestamp DESC);
+CREATE INDEX idx_agent_events_app   ON agent_events(app_id, timestamp DESC);
+CREATE INDEX idx_agent_events_time  ON agent_events(timestamp DESC);

cameleer3-server-app/src/main/resources/db/migration/V6__metrics_retention.sql

@@ -0,0 +1,6 @@
+-- Retention: drop agent_metrics chunks older than 90 days
+SELECT add_retention_policy('agent_metrics', INTERVAL '90 days', if_not_exists => true);
+
+-- Compression: compress agent_metrics chunks older than 7 days
+ALTER TABLE agent_metrics SET (timescaledb.compress);
+SELECT add_compression_policy('agent_metrics', INTERVAL '7 days', if_not_exists => true);