feat: implement hooks, plugins, session forks, and vim motions

Add 4 major features to codetyper-cli:

- Hooks System: Lifecycle hooks (PreToolUse, PostToolUse, SessionStart,
  SessionEnd, UserPromptSubmit, Stop) with exit code control flow
- Plugin System: Custom tools, commands, and hooks via plugin manifest
- Session Forking: Snapshots, rewind, fork, and switch between branches
- Vim Motions: Normal/Insert/Command/Visual modes with keyboard navigation

New files:
- src/types/{hooks,plugin,session-fork,vim}.ts
- src/constants/{hooks,plugin,session-fork,vim}.ts
- src/services/{hooks-service,plugin-loader,plugin-service,session-fork-service}.ts
- src/stores/vim-store.ts (vanilla)
- src/tui/hooks/{useVimMode,useVimStore,useTodoStore,useThemeStore}.ts
- src/tui/components/VimStatusLine.tsx

Modified:
- src/services/agent.ts (hook integration)
- src/tools/index.ts (plugin tool registration)
- src/stores/{todo-store,theme-store}.ts (converted to vanilla)
- TUI components (updated hook imports)

src/interfaces/AppProps.ts

@@ -5,6 +5,12 @@
  */
 
 import type { AgentConfig } from "@/types/agent-config";
+import type { PastedImage } from "@/types/image";
+
+export interface SubmitOptions {
+  /** Pasted images to include with the message */
+  images?: PastedImage[];
+}
 
 export interface AppProps {
   /** Unique session identifier */
@@ -18,7 +24,7 @@ export interface AppProps {
   /** Application version */
   version: string;
   /** Called when user submits a message */
-  onSubmit: (message: string) => Promise<void>;
+  onSubmit: (message: string, options?: SubmitOptions) => Promise<void>;
   /** Called when user exits the application */
   onExit: () => void;
   /** Called when user executes a slash command */

src/interfaces/PastedContent.ts

@@ -2,6 +2,8 @@
  * Interface for tracking pasted content with virtual text
  */
 
+import type { PastedImage } from "@/types/image";
+
 export interface PastedContent {
   /** Unique identifier for the pasted block */
   id: string;
@@ -22,9 +24,12 @@ export interface PasteState {
   pastedBlocks: Map<string, PastedContent>;
   /** Counter for generating unique IDs */
   pasteCounter: number;
+  /** List of pasted images */
+  pastedImages: PastedImage[];
 }
 
 export const createInitialPasteState = (): PasteState => ({
   pastedBlocks: new Map(),
   pasteCounter: 0,
+  pastedImages: [],
 });