refactor(types): move shared types from renderer to shared directory

- Move type definitions from src/renderer/src/types/ to src/shared/types/
- Add @shared/* path alias to tsconfig.node.json and tsconfig.web.json
- Update all imports from @renderer/types/* to @shared/types/*
- Update AGENTS.md with new directory structure and path alias

This fixes architecture violation where main/preload processes imported
from renderer directory. Types are now properly shared across all processes.

tsconfig.web.json

@@ -1,13 +1,12 @@
 {
   "extends": "@electron-toolkit/tsconfig/tsconfig.web.json",
-  "include": [
-    "src/renderer/src/**/*"
-  ],
+  "include": ["src/renderer/src/**/*", "src/shared/**/*"],
   "compilerOptions": {
     "composite": true,
     "baseUrl": ".",
     "paths": {
-      "@renderer/*": ["src/renderer/src/*"]
+      "@renderer/*": ["src/renderer/src/*"],
+      "@shared/*": ["src/shared/*"]
     }
   }
-}
+}