T-233: TS IPC wrappers (terminals.ts) + useTerminalsStore (Zustand, optimistic open/close)

[mpiton]

Goal

Frontend plumbing for terminals. Add src/shared/ipc/terminals.ts (typed wrappers around the 5 IPC commands) and src/features/terminals/store.ts (Zustand store tracking open terminals, focused id, optimistic open/close).

Store shape:

type TerminalsState = {
  byId: Record<TerminalId, TerminalSnapshot>;
  order: TerminalId[];
  focusedId: TerminalId | null;
  open(spec: OpenSpec): Promise<TerminalId>;
  close(id: TerminalId): Promise<void>;
  focus(id: TerminalId): void;
  hydrateFromBackend(): Promise<void>;
};

Acceptance criteria

• src/shared/ipc/terminals.ts exports invokeTerminalsOpen, invokeTerminalsWrite, invokeTerminalsResize, invokeTerminalsClose, invokeTerminalsList, all typed via generated DTOs
• useTerminalsStore covers open / close / focus / hydrate with optimistic updates + rollback on IPC error
• Subscribe to terminal:chunk and terminal:exited via listen() on store init; cleanup unlisten on teardown
• Unit tests with vitest:
  • it("should open a terminal optimistically and roll back on error")
  • it("should mark a terminal as exited when terminal:exited event arrives")
  • it("should focus a newly opened terminal")
• No prop drilling > 2 levels (CLAUDE.md rule)
• pnpm exec oxlint . --max-warnings=0 green; pnpm exec tsc -b green

Files to create/modify

• create src/shared/ipc/terminals.ts
• create src/features/terminals/store.ts
• create src/features/terminals/store.test.ts

References

• CLAUDE.md §Conventions TypeScript / React
• Mirror patterns from src/features/projects/store.ts and src/features/kanban/store.ts

Dependencies

Blocked by T-232.