feat(grafana): add GlitchTip error tracking dashboard

- Add PostgreSQL datasource pointing to GlitchTip database
- Add Error Tracking dashboard with 7 panels:
  - Total Open Issues (stat)
  - Issues by Project (pie chart)
  - Total Events (stat)
  - Projects Tracked (stat)
  - Resolved vs Unresolved (stat)
  - New Issues Over Time (stacked bar chart, 30 days)
  - Recent Issues (table with 50 latest, color-coded levels)
- Dashboard links to GlitchTip UI for detailed investigation

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

docker/grafana/provisioning/datasources/glitchtip.yml

@@ -0,0 +1,23 @@
+# GlitchTip PostgreSQL Datasource
+# Enables error tracking dashboards in Grafana
+
+apiVersion: 1
+
+datasources:
+  - name: GlitchTip
+    type: postgres
+    access: proxy
+    url: postgres:5432
+    user: postgres
+    secureJsonData:
+      password: ${POSTGRES_PASSWORD}
+    jsonData:
+      database: glitchtip
+      sslmode: disable
+      maxOpenConns: 5
+      maxIdleConns: 2
+      connMaxLifetime: 14400
+      postgresVersion: 1600
+      timescaledb: false
+    isDefault: false
+    editable: true