feat(gateway): wire clarify tool with inline keyboard buttons on Telegram (#24199)

The clarify tool returned 'not available in this execution context' for
every gateway-mode agent because gateway/run.py never passed
clarify_callback into the AIAgent constructor. Schema actively encouraged
calling it; users never saw the question.

Changes:

- tools/clarify_gateway.py — new event-based primitive mirroring
  tools/approval.py: register/wait_for_response/resolve_gateway_clarify
  with per-session FIFO, threading.Event blocking with 1s heartbeat
  slices (so the inactivity watchdog keeps ticking), and
  clear_session for boundary cleanup.

- gateway/platforms/base.py — abstract send_clarify with a numbered-text
  fallback so every adapter (Discord, Slack, WhatsApp, Signal, Matrix,
  etc.) gets a working clarify out of the box. Plus an active-session
  bypass: when the agent is blocked on a text-awaiting clarify, the next
  non-command message routes inline to the runner's intercept instead
  of being queued + triggering an interrupt. Same shape as the /approve
  deadlock fix from PR #4926.

- gateway/platforms/telegram.py — concrete send_clarify renders one
  inline button per choice plus '✏️ Other (type answer)'. cl: callback
  handler resolves numeric choices immediately, flips to text-capture
  mode for Other, with the same authorization guards as exec/slash
  approvals.

- gateway/run.py — clarify_callback wired at the cached-agent per-turn
  callback assignment site (only the user-facing agent path; cron and
  hygiene-compress agents have no human attached). Bridges sync→async
  via run_coroutine_threadsafe, blocks with the configured timeout, and
  returns a '[user did not respond within Xm]' sentinel on timeout so
  the agent adapts rather than pinning the running-agent guard. Text-
  intercept added to _handle_message before slash-confirm intercept
  (skipping slash commands). clear_session called in the run's finally
  to cancel any orphan entries.

- hermes_cli/config.py — agent.clarify_timeout default 600s.

- website/docs/user-guide/messaging/telegram.md — Interactive Prompts
  section.

Tests:

- tests/tools/test_clarify_gateway.py (14 tests) — full primitive
  coverage: button resolve, open-ended auto-await, Other flip, timeout
  None, unknown-id idempotency, clear_session cancellation, FIFO
  ordering, register/unregister notify, config default.

- tests/gateway/test_telegram_clarify_buttons.py (12 tests) — render
  paths (multi-choice/open-ended/long-label/HTML-escape/not-connected),
  callback dispatch (numeric resolve/Other flip/already-resolved/
  unauthorized/invalid-token), and base-adapter text fallback.

Out of scope: bot-to-bot, guest mode, checklists, poll media, live
photos. Closes #24191.

gateway/platforms/base.py

@@ -1743,6 +1743,55 @@ class BasePlatformAdapter(ABC):
         """
         return SendResult(success=False, error="Not supported")
 
+    async def send_clarify(
+        self,
+        chat_id: str,
+        question: str,
+        choices: Optional[list],
+        clarify_id: str,
+        session_key: str,
+        metadata: Optional[Dict[str, Any]] = None,
+    ) -> SendResult:
+        """Send a clarify prompt to the user.
+
+        Two render modes:
+
+          * **Multiple choice** (``choices`` is a non-empty list) — adapters
+            that override this should render inline buttons (one per choice
+            plus a final "Other" / free-text option).  Button callbacks
+            MUST resolve via
+            ``tools.clarify_gateway.resolve_gateway_clarify(clarify_id, response)``
+            with the chosen string.  Picking the "Other" button calls
+            ``mark_awaiting_text(clarify_id)`` so the next message in the
+            session is captured as the response.
+
+          * **Open-ended** (``choices`` is None or empty) — render the
+            question as a plain text message; the next user message in the
+            session is captured by the gateway's text-intercept and
+            resolves the clarify automatically (see
+            ``GatewayRunner._maybe_intercept_clarify_text``).
+
+        The default implementation falls back to a numbered text list,
+        which works on every platform — the user replies with a number
+        ("2") or with the literal choice text, and the gateway intercepts
+        and resolves.  Adapters with native button UIs (Telegram, Discord)
+        SHOULD override this for a richer UX.
+        """
+        if choices:
+            lines = [f"❓ {question}", ""]
+            for i, choice in enumerate(choices, start=1):
+                lines.append(f"  {i}. {choice}")
+            lines.append("")
+            lines.append("Reply with the number, the option text, or your own answer.")
+            text = "\n".join(lines)
+        else:
+            text = f"❓ {question}"
+        return await self.send(
+            chat_id=chat_id,
+            content=text,
+            metadata=metadata,
+        )
+
     async def send_private_notice(
         self,
         chat_id: str,
@@ -2831,6 +2880,58 @@ class BasePlatformAdapter(ABC):
                     logger.error("[%s] Command '/%s' dispatch failed: %s", self.name, cmd, e, exc_info=True)
                 return
 
+            # Clarify text-capture bypass: if the agent is blocked on a
+            # clarify_tool call awaiting a free-form text response (open-
+            # ended clarify, or user picked "Other"), the next non-command
+            # message in this session MUST reach the runner so the
+            # clarify-intercept can resolve it and unblock the agent.
+            #
+            # Without this bypass: the message gets queued in
+            # _pending_messages AND triggers an interrupt, killing the
+            # agent run mid-clarify and discarding the user's answer.
+            # Same shape as the /approve deadlock fix (PR #4926) — both
+            # cases are "agent thread blocked on Event.wait, message must
+            # reach the resolver before being treated as a new turn."
+            if not cmd:
+                try:
+                    from tools import clarify_gateway as _clarify_mod
+                    _has_text_clarify = (
+                        _clarify_mod.get_pending_for_session(session_key) is not None
+                    )
+                except Exception:
+                    _has_text_clarify = False
+
+                if _has_text_clarify:
+                    logger.debug(
+                        "[%s] Routing message to clarify text-intercept for %s",
+                        self.name, session_key,
+                    )
+                    try:
+                        _thread_meta = _thread_metadata_for_source(
+                            event.source, _reply_anchor_for_event(event)
+                        )
+                        response = await self._message_handler(event)
+                        _text, _eph_ttl = self._unwrap_ephemeral(response)
+                        if _text:
+                            _r = await self._send_with_retry(
+                                chat_id=event.source.chat_id,
+                                content=_text,
+                                reply_to=_reply_anchor_for_event(event),
+                                metadata=_thread_meta,
+                            )
+                            if _eph_ttl > 0 and _r.success and _r.message_id:
+                                self._schedule_ephemeral_delete(
+                                    chat_id=event.source.chat_id,
+                                    message_id=_r.message_id,
+                                    ttl_seconds=_eph_ttl,
+                                )
+                    except Exception as e:
+                        logger.error(
+                            "[%s] Clarify text-intercept dispatch failed: %s",
+                            self.name, e, exc_info=True,
+                        )
+                    return
+
             if self._busy_session_handler is not None:
                 try:
                     if await self._busy_session_handler(event, session_key):