feat: handle Elicitation and ElicitationResult hook events (#223)

Parses [Elicitation Hook] and [ElicitationResult Hook] from Claude Code
stderr, emits claude:elicitation and claude:elicitation-result Tauri
events, and renders an ElicitationModal for MCP server input requests.

src-tauri/src/types.rs

@@ -280,6 +280,26 @@ pub struct UserQuestionEvent {
     pub conversation_id: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ElicitationEvent {
+    pub message: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub server_name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub request_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ElicitationResultEvent {
+    pub action: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub request_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AgentStartEvent {
     pub tool_use_id: String,
@@ -566,4 +586,63 @@ mod tests {
             panic!("Expected RateLimitEvent variant");
         }
     }
+
+    #[test]
+    fn test_elicitation_event_serialization() {
+        let event = ElicitationEvent {
+            message: "Please provide the API endpoint".to_string(),
+            server_name: Some("my-server".to_string()),
+            request_id: Some("req-123".to_string()),
+            conversation_id: Some("conv-abc".to_string()),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"message\":\"Please provide the API endpoint\""));
+        assert!(serialized.contains("\"server_name\":\"my-server\""));
+        assert!(serialized.contains("\"request_id\":\"req-123\""));
+        assert!(serialized.contains("\"conversation_id\":\"conv-abc\""));
+    }
+
+    #[test]
+    fn test_elicitation_event_omits_none_fields() {
+        let event = ElicitationEvent {
+            message: "Enter your token".to_string(),
+            server_name: None,
+            request_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"message\":\"Enter your token\""));
+        assert!(!serialized.contains("server_name"));
+        assert!(!serialized.contains("request_id"));
+        assert!(!serialized.contains("conversation_id"));
+    }
+
+    #[test]
+    fn test_elicitation_result_event_serialization() {
+        let event = ElicitationResultEvent {
+            action: "accept".to_string(),
+            request_id: Some("req-123".to_string()),
+            conversation_id: Some("conv-abc".to_string()),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"action\":\"accept\""));
+        assert!(serialized.contains("\"request_id\":\"req-123\""));
+    }
+
+    #[test]
+    fn test_elicitation_result_event_cancel_omits_none_fields() {
+        let event = ElicitationResultEvent {
+            action: "cancel".to_string(),
+            request_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"action\":\"cancel\""));
+        assert!(!serialized.contains("request_id"));
+        assert!(!serialized.contains("conversation_id"));
+    }
 }