feat: add AskUserQuestion tool support (#60)

## Summary

Implements support for Claude's `AskUserQuestion` tool, allowing Claude to ask the user questions with multiple choice options during a conversation.

## Changes

- Add `UserQuestionEvent` and `QuestionOption` types (Rust and TypeScript)
- Detect `AskUserQuestion` in permission denials and emit `claude:question` event
- Create `UserQuestionModal` component with option selection and custom answer input
- Use stop/reconnect approach (same as `PermissionModal`) since Claude API doesn't accept tool_result for permission-denied tools
- Add `pendingQuestion` to conversation store and `hasQuestionPending` derived store

## Technical Notes

We discovered that Claude Code's permission denial system doesn't allow sending tool results back directly - the API rejects them with "unexpected tool_use_id found in tool_result blocks". The solution was to use the same stop/reconnect pattern that permissions use: stop the session, reconnect with context, and include the user's answer in the context restoration message.

## Test Plan

- [x] Build compiles without errors (Rust + TypeScript)
- [x] Question modal appears when Claude uses `AskUserQuestion`
- [x] Can select options and submit answer
- [x] Answer is properly restored to Claude after reconnect

Closes #51

---

✨ This PR was created with help from Hikari~ 🌸

Co-authored-by: Hikari <hikari@nhcarrigan.com>
Reviewed-on: #60

src/lib/stores/claude.ts

@@ -21,6 +21,7 @@ export const claudeStore = {
   currentWorkingDirectory: conversationsStore.currentWorkingDirectory,
   terminalLines: conversationsStore.terminalLines,
   pendingPermission: conversationsStore.pendingPermission,
+  pendingQuestion: conversationsStore.pendingQuestion,
   isProcessing: conversationsStore.isProcessing,
   grantedTools: conversationsStore.grantedTools,
   pendingRetryMessage: conversationsStore.pendingRetryMessage,
@@ -49,6 +50,10 @@ export const claudeStore = {
   clearPermission: conversationsStore.clearPermission,
   requestPermissionForConversation: conversationsStore.requestPermissionForConversation,
   clearPermissionForConversation: conversationsStore.clearPermissionForConversation,
+  requestQuestion: conversationsStore.requestQuestion,
+  clearQuestion: conversationsStore.clearQuestion,
+  requestQuestionForConversation: conversationsStore.requestQuestionForConversation,
+  clearQuestionForConversation: conversationsStore.clearQuestionForConversation,
   grantTool: conversationsStore.grantTool,
   revokeAllTools: conversationsStore.revokeAllTools,
   isToolGranted: conversationsStore.isToolGranted,
@@ -89,6 +94,11 @@ export const hasPermissionPending = derived(
   ($conversation) => $conversation?.pendingPermission !== null
 );
 
+export const hasQuestionPending = derived(
+  claudeStore.activeConversation,
+  ($conversation) => $conversation?.pendingQuestion !== null
+);
+
 // Derived store to check if Claude is currently processing (can be interrupted)
 export const isClaudeProcessing = derived(
   [claudeStore.connectionStatus, characterState],

src/lib/stores/conversations.ts

@@ -1,5 +1,10 @@
 import { writable, derived, get } from "svelte/store";
-import type { TerminalLine, ConnectionStatus, PermissionRequest } from "$lib/types/messages";
+import type {
+  TerminalLine,
+  ConnectionStatus,
+  PermissionRequest,
+  UserQuestionEvent,
+} from "$lib/types/messages";
 import type { CharacterState } from "$lib/types/states";
 import { cleanupConversationTracking } from "$lib/tauri";
 import { characterState } from "$lib/stores/character";
@@ -15,6 +20,7 @@ export interface Conversation {
   isProcessing: boolean;
   grantedTools: Set<string>;
   pendingPermission: PermissionRequest | null;
+  pendingQuestion: UserQuestionEvent | null;
   createdAt: Date;
   lastActivityAt: Date;
 }
@@ -48,6 +54,7 @@ function createConversationsStore() {
       isProcessing: false,
       grantedTools: new Set(),
       pendingPermission: null,
+      pendingQuestion: null,
       createdAt: new Date(),
       lastActivityAt: new Date(),
     };
@@ -98,6 +105,7 @@ function createConversationsStore() {
     activeConversation,
     ($conv) => $conv?.pendingPermission || null
   );
+  const pendingQuestion = derived(activeConversation, ($conv) => $conv?.pendingQuestion || null);
 
   return {
     // Expose derived stores for compatibility
@@ -106,6 +114,7 @@ function createConversationsStore() {
     currentWorkingDirectory: { subscribe: currentWorkingDirectory.subscribe },
     terminalLines: { subscribe: terminalLines.subscribe },
     pendingPermission: { subscribe: pendingPermission.subscribe },
+    pendingQuestion: { subscribe: pendingQuestion.subscribe },
     isProcessing: { subscribe: isProcessing.subscribe },
     grantedTools: { subscribe: grantedTools.subscribe },
     pendingRetryMessage: { subscribe: pendingRetryMessage.subscribe },
@@ -199,6 +208,52 @@ function createConversationsStore() {
         return convs;
       });
     },
+    requestQuestion: (question: UserQuestionEvent) => {
+      const activeId = get(activeConversationId);
+      if (!activeId) return;
+
+      conversations.update((convs) => {
+        const conv = convs.get(activeId);
+        if (conv) {
+          conv.pendingQuestion = question;
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+    clearQuestion: () => {
+      const activeId = get(activeConversationId);
+      if (!activeId) return;
+
+      conversations.update((convs) => {
+        const conv = convs.get(activeId);
+        if (conv) {
+          conv.pendingQuestion = null;
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+    requestQuestionForConversation: (conversationId: string, question: UserQuestionEvent) => {
+      conversations.update((convs) => {
+        const conv = convs.get(conversationId);
+        if (conv) {
+          conv.pendingQuestion = question;
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+    clearQuestionForConversation: (conversationId: string) => {
+      conversations.update((convs) => {
+        const conv = convs.get(conversationId);
+        if (conv) {
+          conv.pendingQuestion = null;
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
     setPendingRetryMessage: (message: string | null) => pendingRetryMessage.set(message),
 
     // Conversation management