chore: clean up root folder by moving config files

- Move renovate.json to .github/renovate.json
- Move electron-builder.yml to electron/electron-builder.yml
- Move electron.d.ts to electron/electron.d.ts
- Delete proxy.ts (unused dead code)
- Update package.json dist scripts with --config flag
- Use tsconfig.json files array for electron.d.ts (bypasses exclude)

Reduces git-tracked root files from 23 to 19.

.github/renovate.json

@@ -0,0 +1,40 @@
+{
+    "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+    "extends": ["config:recommended"],
+    "schedule": ["after 10am on saturday"],
+    "timezone": "Asia/Tokyo",
+    "packageRules": [
+        {
+            "matchUpdateTypes": ["minor", "patch"],
+            "matchPackagePatterns": ["*"],
+            "groupName": "minor and patch dependencies",
+            "automerge": true
+        },
+        {
+            "matchUpdateTypes": ["major"],
+            "matchPackagePatterns": ["*"],
+            "automerge": false
+        },
+        {
+            "matchPackagePatterns": ["@ai-sdk/*"],
+            "groupName": "AI SDK packages"
+        },
+        {
+            "matchPackagePatterns": ["@radix-ui/*"],
+            "groupName": "Radix UI packages"
+        },
+        {
+            "matchPackagePatterns": ["electron", "electron-builder"],
+            "groupName": "Electron packages",
+            "automerge": false
+        },
+        {
+            "matchPackagePatterns": ["@ai-sdk/*", "ai", "next"],
+            "groupName": "Core framework packages",
+            "automerge": false
+        }
+    ],
+    "vulnerabilityAlerts": {
+        "enabled": true
+    }
+}