feat(ui): add configurable text justification activity setting (#212)

* fix(server): improve external server and error handling

- Skip OpenCode shutdown when using external server
  (OPENCODE_SKIP_START=true)
- Return 404 status for non-existent directories instead of
  empty array
- Move error logging before response handling

* feat(ui): add configurable text justification activity setting

- Replace hardcoded ENABLE_TEXT_JUSTIFICATION_ACTIVITY constant with
  dynamic showTextJustificationActivity setting in useUIStore
- Add toggle UI in Chat settings section (Settings > Chat)
- Add setting to DesktopSettings type for cross-runtime persistence
- Default value is false (matching original constant behavior)

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Co-authored-by: iiyangdianfeng <goodydfwow@gmail.com>

packages/ui/src/lib/desktop.ts

@@ -51,6 +51,7 @@ export type DesktopSettings = {
   securityScopedBookmarks?: string[];
   pinnedDirectories?: string[];
   showReasoningTraces?: boolean;
+  showTextJustificationActivity?: boolean;
   autoDeleteEnabled?: boolean;
   autoDeleteAfterDays?: number;
   defaultModel?: string; // format: "provider/model"