feat: add serverUrl configuration support with settings.json fallback

Implement serverUrl initialization following the cliApiToken design pattern:
- Environment variable HAPI_SERVER_URL (highest priority, allows temporary override)
- settings.json serverUrl field (user persistent configuration)
- Default value 'http://localhost:3006' (fallback)

Changes:
- Add serverUrl field to Settings interface (persistence.ts)
- Convert serverUrl to private property with getter/setter (configuration.ts)
- Create initializeServerUrl module to load from settings (serverUrlInit.ts)
- Integrate serverUrl initialization in tokenInit flow (tokenInit.ts)
- Skip auto-start when serverUrl is configured in settings (autoStartServer.ts)

cli/src/persistence.ts

@@ -17,6 +17,8 @@ interface Settings {
   machineIdConfirmedByServer?: boolean
   daemonAutoStartWhenRunningHappy?: boolean
   cliApiToken?: string
+  // Server URL for API connections (priority: env HAPI_SERVER_URL > this > default)
+  serverUrl?: string
 }
 
 const defaultSettings: Settings = {}