Migrate frontend from JavaScript to TypeScript

- Rename all 54 .js files to .ts, update esbuild entry point
- Add tsconfig.json, TypeScript devDependency, typecheck script
- Create types.ts with 25+ interfaces matching backend Pydantic schemas
  (Device, OutputTarget, ColorStripSource, PatternTemplate, ValueSource,
  AudioSource, PictureSource, ScenePreset, SyncClock, Automation, etc.)
- Make DataCache generic (DataCache<T>) with typed state instances
- Type all state variables in state.ts with proper entity types
- Type all create*Card functions with proper entity interfaces
- Type all function parameters and return types across all 54 files
- Type core component constructors (CardSection, IconSelect, EntitySelect,
  FilterList, TagInput, TreeNav, Modal) with exported option interfaces
- Add comprehensive global.d.ts for window function declarations
- Type fetchWithAuth with FetchAuthOpts interface
- Remove all (window as any) casts in favor of global.d.ts declarations
- Zero tsc errors, esbuild bundle unchanged

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

server/package-lock.json

@@ -13,7 +13,8 @@
         "elkjs": "^0.11.1"
       },
       "devDependencies": {
-        "esbuild": "^0.27.4"
+        "esbuild": "^0.27.4",
+        "typescript": "^5.9.3"
       }
     },
     "node_modules/@esbuild/aix-ppc64": {
@@ -493,6 +494,19 @@
         "@esbuild/win32-ia32": "0.27.4",
         "@esbuild/win32-x64": "0.27.4"
       }
+    },
+    "node_modules/typescript": {
+      "version": "5.9.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
+      "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
+      "dev": true,
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=14.17"
+      }
     }
   },
   "dependencies": {
@@ -729,6 +743,12 @@
         "@esbuild/win32-ia32": "0.27.4",
         "@esbuild/win32-x64": "0.27.4"
       }
+    },
+    "typescript": {
+      "version": "5.9.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
+      "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
+      "dev": true
     }
   }
 }