Remove Electron settings panel (breaking change)

- Remove electron/settings/ folder
- Remove config-manager.ts and settings-window.ts
- Remove Configuration menu from app menu
- Remove config-presets IPC handlers
- Update README.md
- Clean up electron.d.ts

Note: This is a breaking change - users will lose existing presets

electron.d.ts

@@ -2,29 +2,6 @@
  * Type declarations for Electron API exposed via preload script
  */
 
-/** Configuration preset interface */
-interface ConfigPreset {
-    id: string
-    name: string
-    createdAt: number
-    updatedAt: number
-    config: {
-        AI_PROVIDER?: string
-        AI_MODEL?: string
-        AI_API_KEY?: string
-        AI_BASE_URL?: string
-        TEMPERATURE?: string
-        [key: string]: string | undefined
-    }
-}
-
-/** Result of applying a preset */
-interface ApplyPresetResult {
-    success: boolean
-    error?: string
-    env?: Record<string, string>
-}
-
 declare global {
     interface Window {
         /** Main window Electron API */
@@ -46,29 +23,7 @@ declare global {
             /** Save data to file via save dialog */
             saveFile: (data: string) => Promise<boolean>
         }
-
-        /** Settings window Electron API */
-        settingsAPI?: {
-            /** Get all configuration presets */
-            getPresets: () => Promise<ConfigPreset[]>
-            /** Get current preset ID */
-            getCurrentPresetId: () => Promise<string | null>
-            /** Get current preset */
-            getCurrentPreset: () => Promise<ConfigPreset | null>
-            /** Save (create or update) a preset */
-            savePreset: (preset: {
-                id?: string
-                name: string
-                config: Record<string, string | undefined>
-            }) => Promise<ConfigPreset>
-            /** Delete a preset */
-            deletePreset: (id: string) => Promise<boolean>
-            /** Apply a preset (sets environment variables and restarts server) */
-            applyPreset: (id: string) => Promise<ApplyPresetResult>
-            /** Close settings window */
-            close: () => void
-        }
     }
 }
 
-export { ConfigPreset, ApplyPresetResult }
+export {}