Feature: Auto-create incidents after 10 failed checks with rich descriptions

- Add description and failed_check_count fields to incidents table
- Update handleIncident() to use configurable threshold (default 10 checks)
- Auto-generate incident description with:
  - Number of consecutive failures
  - Last error message/reason
  - First failure timestamp
- Add API endpoints: GET/POST /api/settings/incident-threshold
- Add UI settings field to configure incident failure threshold
- Server: Get threshold from database settings (persistent across restarts)
- Default threshold: 10 consecutive failed checks per resource

client/build/asset-manifest.json

@@ -1,15 +1,15 @@
 {
   "files": {
     "main.css": "/static/css/main.2e6b09f5.css",
-    "main.js": "/static/js/main.7ec306fb.js",
+    "main.js": "/static/js/main.19ff8743.js",
     "static/js/453.d456ce70.chunk.js": "/static/js/453.d456ce70.chunk.js",
     "index.html": "/index.html",
     "main.2e6b09f5.css.map": "/static/css/main.2e6b09f5.css.map",
-    "main.7ec306fb.js.map": "/static/js/main.7ec306fb.js.map",
+    "main.19ff8743.js.map": "/static/js/main.19ff8743.js.map",
     "453.d456ce70.chunk.js.map": "/static/js/453.d456ce70.chunk.js.map"
   },
   "entrypoints": [
     "static/css/main.2e6b09f5.css",
-    "static/js/main.7ec306fb.js"
+    "static/js/main.19ff8743.js"
   ]
 }