feat(chatto): add interactive prompt state containers

adapter.py

@@ -357,6 +357,39 @@ class _RoomRoster:
     unfetched: int = 0
 
 
+@dataclass
+class _ClarifyPrompt:
+    """State for a reaction-driven clarify prompt posted to a Chatto room."""
+
+    clarify_id: str
+    choices: list[str]
+    session_key: str
+    chat_id: str
+    message_id: str
+    resolved: bool = False
+    awaiting_text: bool = False
+    resolved_by: str | None = None
+    resolved_choice: str | None = None
+    expires_at: float = 0.0
+
+
+@dataclass
+class _ApprovalPrompt:
+    """State for a reaction-driven exec-approval prompt posted to a Chatto room."""
+
+    session_key: str
+    chat_id: str
+    message_id: str
+    choices_map: dict[str, str]  # emoji -> choice
+    resolved: bool = False
+    resolved_by: str | None = None
+    resolved_choice: str | None = None
+    expires_at: float = 0.0
+
+
+INTERACTIVE_PROMPT_TIMEOUT_SECONDS = 300
+
+
 _UNSEEDED: Final = object()
 """Sentinel: nothing is known yet about how far this thread's session reaches.
 
@@ -482,6 +515,13 @@ class ChattoAdapter(BasePlatformAdapter):
         # Member directory cache: user_id -> user info dict
         self._user_cache: dict[str, User] = {}
 
+        # Interactive prompt registries (clarify + exec-approval), keyed by
+        # message_id. Reverse lookup _clarify_id_to_message supports
+        # retire_clarify_card.
+        self._clarify_prompts: dict[str, _ClarifyPrompt] = {}
+        self._approval_prompts: dict[str, _ApprovalPrompt] = {}
+        self._clarify_id_to_message: dict[str, str] = {}
+
         # Chattolib client cache and lock for async access.
         self._chatto_client: ChattoClient | None = None
         self._chatto_client_lock: asyncio.Lock = asyncio.Lock()