Revert "feat(settings): add auto-launch on system startup feature"

This reverts commit ba336fc416.

Reason: Found issues that need to be addressed before reintroducing
the auto-launch feature. Will reimplement with fixes.

src/hooks/useSettingsForm.ts

@@ -82,7 +82,6 @@ export function useSettingsForm(): UseSettingsFormResult {
       minimizeToTrayOnClose: data.minimizeToTrayOnClose ?? true,
       enableClaudePluginIntegration:
         data.enableClaudePluginIntegration ?? false,
-      launchOnStartup: data.launchOnStartup ?? false,
       claudeConfigDir: sanitizeDir(data.claudeConfigDir),
       codexConfigDir: sanitizeDir(data.codexConfigDir),
       language: normalizedLanguage,
@@ -102,7 +101,6 @@ export function useSettingsForm(): UseSettingsFormResult {
             showInTray: true,
             minimizeToTrayOnClose: true,
             enableClaudePluginIntegration: false,
-            launchOnStartup: false,
             language: readPersistedLanguage(),
           } as SettingsFormState);
 
@@ -137,7 +135,6 @@ export function useSettingsForm(): UseSettingsFormResult {
         minimizeToTrayOnClose: serverData.minimizeToTrayOnClose ?? true,
         enableClaudePluginIntegration:
           serverData.enableClaudePluginIntegration ?? false,
-        launchOnStartup: serverData.launchOnStartup ?? false,
         claudeConfigDir: sanitizeDir(serverData.claudeConfigDir),
         codexConfigDir: sanitizeDir(serverData.codexConfigDir),
         language: normalizedLanguage,