refactor: organize features and standardize frontend tooling

Colocate feature views, components, stores, and upload logic; centralize shared map utilities without changing API behavior.

Add ESLint, Prettier, EditorConfig, and VS Code settings; standardize four-space indentation and document the project structure and checks.

Validation: npm run check, npm run build, and git diff --check.

tsconfig.json

@@ -1,7 +1,4 @@
 {
-  "files": [],
-  "references": [
-    { "path": "./tsconfig.app.json" },
-    { "path": "./tsconfig.node.json" }
-  ]
+    "files": [],
+    "references": [{ "path": "./tsconfig.app.json" }, { "path": "./tsconfig.node.json" }]
 }