WIP: Add hook API for dynamic tool control with plan-mode hook example

- Add pi.getTools() and pi.setTools(toolNames) to HookAPI
- Hooks can now enable/disable tools dynamically
- Changes take effect on next agent turn

New example hook: plan-mode.ts
- Claude Code-style read-only exploration mode
- /plan command toggles plan mode on/off
- Plan mode tools: read, bash, grep, find, ls
- Edit/write tools disabled in plan mode
- Injects context telling agent about restrictions
- After each response, prompts to execute/stay/refine
- State persists across sessions

packages/coding-agent/src/core/hooks/index.ts

@@ -4,11 +4,13 @@ export {
 	loadHooks,
 	type AppendEntryHandler,
 	type BranchHandler,
+	type GetToolsHandler,
 	type LoadedHook,
 	type LoadHooksResult,
 	type NavigateTreeHandler,
 	type NewSessionHandler,
 	type SendMessageHandler,
+	type SetToolsHandler,
 } from "./loader.js";
 export { execCommand, HookRunner, type HookErrorListener } from "./runner.js";
 export { wrapToolsWithHooks, wrapToolWithHooks } from "./tool-wrapper.js";