fix: address nitpick feedback from PR #423

## Security Fix (Command Injection)
- Use `execFile` with argument arrays instead of string interpolation
- Add `safeOpenInEditor` helper that properly handles `open -a` commands
- Validate that worktreePath is an absolute path before execution
- Prevents shell metacharacter injection attacks

## Shared Type Definition
- Move `EditorInfo` interface to `@automaker/types` package
- Server and UI now import from shared package to prevent drift
- Re-export from use-available-editors.ts for convenience

## Remove Unused Code
- Remove unused `defaultEditorName` prop from WorktreeActionsDropdown
- Remove prop from WorktreeTab component interface
- Remove useDefaultEditor hook usage from WorktreePanel
- Export new hooks from hooks/index.ts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/ui/src/components/views/board-view/worktree-panel/hooks/index.ts

@@ -2,5 +2,5 @@ export { useWorktrees } from './use-worktrees';
 export { useDevServers } from './use-dev-servers';
 export { useBranches } from './use-branches';
 export { useWorktreeActions } from './use-worktree-actions';
-export { useDefaultEditor } from './use-default-editor';
 export { useRunningFeatures } from './use-running-features';
+export { useAvailableEditors, useEffectiveDefaultEditor } from './use-available-editors';

apps/ui/src/components/views/board-view/worktree-panel/hooks/use-available-editors.ts

@@ -2,13 +2,12 @@ import { useState, useEffect, useCallback, useMemo } from 'react';
 import { createLogger } from '@automaker/utils/logger';
 import { getElectronAPI } from '@/lib/electron';
 import { useAppStore } from '@/store/app-store';
+import type { EditorInfo } from '@automaker/types';
 
 const logger = createLogger('AvailableEditors');
 
-export interface EditorInfo {
-  name: string;
-  command: string;
-}
+// Re-export EditorInfo for convenience
+export type { EditorInfo };
 
 export function useAvailableEditors() {
   const [editors, setEditors] = useState<EditorInfo[]>([]);