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-tauri/src/bridge_manager.rs

@@ -79,6 +79,14 @@ impl BridgeManager {
         }
     }
 
+    pub fn send_tool_result(&mut self, conversation_id: &str, tool_use_id: &str, result: serde_json::Value) -> Result<(), String> {
+        if let Some(bridge) = self.bridges.get_mut(conversation_id) {
+            bridge.send_tool_result(tool_use_id, result)
+        } else {
+            Err("No Claude instance found for this conversation".to_string())
+        }
+    }
+
     pub fn is_claude_running(&self, conversation_id: &str) -> bool {
         self.bridges.get(conversation_id)
             .map(|b| b.is_running())