feat(astrolabe): add Nextcloud PHP app for MCP server management

Adds a native Nextcloud app "Astroglobe" that provides:
- Personal settings: OAuth authorization for background MCP access
- Admin settings: Server status and vector sync monitoring
- API endpoints for MCP server communication

The app uses PKCE OAuth flow to obtain tokens for the MCP server,
enabling features like background vector sync per ADR-018.

Includes:
- PHP app structure (controllers, services, settings)
- Vue.js frontend components
- Docker compose mount configuration
- Installation hook for development testing
- ADR-018 documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

third_party/astroglobe/.github/dependabot.yml

@@ -0,0 +1,50 @@
+version: 2
+updates:
+  - package-ecosystem: composer
+    directory: "/"
+    schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+    open-pull-requests-limit: 10
+  - package-ecosystem: composer
+    directory: "/vendor-bin/cs-fixer"
+    schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+    open-pull-requests-limit: 10
+  - package-ecosystem: composer
+    directory: "/vendor-bin/openapi-extractor"
+    schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+    open-pull-requests-limit: 10
+  - package-ecosystem: composer
+    directory: "/vendor-bin/phpunit"
+    schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+    open-pull-requests-limit: 10
+  - package-ecosystem: composer
+    directory: "/vendor-bin/psalm"
+    schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+    open-pull-requests-limit: 10
+  - package-ecosystem: npm
+    directory: "/"
+    schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+    open-pull-requests-limit: 10