refactor(store): Extract types from app-store.ts into modular type files

- Create store/types/ directory with 8 modular type files:
  - usage-types.ts: ClaudeUsage, CodexUsage, isClaudeUsageAtLimit
  - ui-types.ts: ViewMode, ThemeMode, KeyboardShortcuts, etc.
  - settings-types.ts: ApiKeys
  - chat-types.ts: ChatMessage, ChatSession, FeatureImage
  - terminal-types.ts: TerminalState, TerminalTab, etc.
  - project-types.ts: Feature, FileTreeNode, ProjectAnalysis
  - state-types.ts: AppState, AppActions interfaces
  - index.ts: Re-exports all types

- Update electron.ts to import from store/types/usage-types
  (breaks circular dependency between electron.ts and app-store.ts)

- Update app-store.ts to import and re-export types for backward
  compatibility - existing imports from @/store/app-store continue
  to work

This is PR 1 of the app-store refactoring plan.

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

apps/ui/src/lib/electron.ts

@@ -1,6 +1,6 @@
 // Type definitions for Electron IPC API
 import type { SessionListItem, Message } from '@/types/electron';
-import type { ClaudeUsageResponse, CodexUsageResponse } from '@/store/app-store';
+import type { ClaudeUsageResponse, CodexUsageResponse } from '@/store/types/usage-types';
 import type {
   IssueValidationVerdict,
   IssueValidationConfidence,