fix(coding-agent): git temp path resolution, add pi list command (#645)

- Fix getGitInstallPath to check scope === 'temporary' directly
- Remove redundant temporary parameter from git methods
- Add 'pi list' command to show installed extensions from settings

packages/coding-agent/src/cli/args.ts

@@ -180,6 +180,7 @@ ${chalk.bold("Commands:")}
   ${APP_NAME} install <source> [-l]    Install extension source and add to settings
   ${APP_NAME} remove <source> [-l]     Remove extension source from settings
   ${APP_NAME} update [source]          Update installed extensions (skips pinned sources)
+  ${APP_NAME} list                     List installed extensions from settings
 
 ${chalk.bold("Options:")}
   --provider <name>              Provider name (default: google)