feat: drag-and-drop dashboard editing, alert dynamic fields

- Replace up/down arrow reorder buttons on dashboard edit page with
  SortableJS drag handles; add POST /d/<id>/edit/reorder endpoint
  accepting ordered widget ID array
- Add {% block extra_scripts %} hook to base.html for page-specific JS
- Add dynamic alert rule field loading via HTMX partial (_rule_fields)
  so metric/threshold fields update when source is changed
- Add docs/plugins/index.yaml.example showing catalog index format

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

docs/plugins/index.yaml.example

@@ -34,6 +34,37 @@ updated: "2026-03-22"
 
 plugins:
 
+  - name: http
+    version: "1.0.0"
+    description: "Synthetic HTTP endpoint monitoring — status code, response time, content match, TLS expiry"
+    author: "FabledScryer"
+    license: "MIT"
+    min_app_version: "0.1.0"
+    repository_url: "https://git.fabledsword.com/bvandeusen/FabledScryer-plugins"
+    homepage: "https://git.fabledsword.com/bvandeusen/FabledScryer-plugins/src/branch/main/http"
+    download_url: "https://git.fabledsword.com/bvandeusen/FabledScryer-plugins/releases/download/http-v1.0.0/http.zip"
+    checksum_sha256: ""
+    tags:
+      - monitoring
+      - http
+      - synthetic
+      - uptime
+
+  - name: docker
+    version: "1.0.0"
+    description: "Docker container status, resource usage, and restart tracking via Docker socket"
+    author: "FabledScryer"
+    license: "MIT"
+    min_app_version: "0.1.0"
+    repository_url: "https://git.fabledsword.com/bvandeusen/FabledScryer-plugins"
+    homepage: "https://git.fabledsword.com/bvandeusen/FabledScryer-plugins/src/branch/main/docker"
+    download_url: "https://git.fabledsword.com/bvandeusen/FabledScryer-plugins/releases/download/docker-v1.0.0/docker.zip"
+    checksum_sha256: ""
+    tags:
+      - containers
+      - docker
+      - infrastructure
+
   - name: traefik
     version: "1.0.0"
     description: "Traefik reverse proxy metrics and access log integration"