feat(telegram): native draft streaming via sendMessageDraft (Bot API 9.5+)

Adds Telegram's native streaming-draft API as a streaming transport so DM
replies render with smooth animated previews as tokens arrive, dropping
the per-edit jitter of the legacy editMessageText polling path.

Adapter contract (gateway/platforms/base.py):
  - supports_draft_streaming(chat_type, metadata) -> bool. Default False.
    Telegram returns True only for DMs and only when the bound python-
    telegram-bot version exposes Bot.send_message_draft (PTB 22.6+).
  - send_draft(chat_id, draft_id, content, metadata) -> SendResult.
    Default raises NotImplementedError. Telegram delegates to PTB's
    send_message_draft. Drafts have no message_id (Bot API contract);
    SendResult.message_id is None on success.

Telegram adapter (gateway/platforms/telegram.py):
  - supports_draft_streaming gates on chat_type='dm' AND PTB capability.
  - send_draft trims to MAX_MESSAGE_LENGTH using utf16_len, threads
    message_thread_id through metadata, and routes failures back as
    SendResult(success=False, error=...) so the consumer can fall back.

Stream consumer (gateway/stream_consumer.py):
  - StreamConsumerConfig gains transport ('auto'|'draft'|'edit'|'off')
    and chat_type fields.
  - run() resolves _use_draft_streaming once via a probe at the top of
    the run, allocating a fresh class-wide draft_id_counter so each
    response animates as its own preview (no animation collision across
    consecutive responses to the same chat).
  - _send_or_edit gains a pre-edit branch: when drafts are active AND
    not finalizing AND no edit-path message_id is established, the
    frame routes through _send_draft_frame instead of edit_message.
    Drafts intentionally do NOT set _already_sent so the gateway's
    final sendMessage path still fires — drafts have no message_id and
    the user needs a real message in their chat history.
  - _reset_segment_state bumps the draft_id when the consumer is in
    draft mode so each text block after a tool boundary animates as a
    fresh preview below the tool-progress bubble (avoids the inter-
    tool-call leak openclaw documented in their #32535).
  - Per-response fallback: any send_draft failure (transient network,
    server reject, capability gap) flips _use_draft_streaming to False
    for the rest of the run, gracefully returning to the edit path.

Gateway config (gateway/config.py):
  - StreamingConfig.transport default flips edit -> auto. The auto path
    is identical to edit on every chat type that doesn't currently
    support drafts (groups, supergroups, forum topics, every non-
    Telegram platform), so the default is backwards-compatible for
    non-DM users.

Lifecycle model (Telegram Bot API 9.5):
  1. sendMessageDraft(chat_id, draft_id, text='') opens the bubble.
  2. Repeated sendMessageDraft calls with the SAME draft_id animate
     the preview as text grows.
  3. Drafts have no message_id and cannot be edited or deleted.
  4. When the response finishes the gateway's normal sendMessage path
     delivers the final answer; the draft preview clears naturally on
     the client and the user sees a real message in their history.

Inspired by PR #3412 by @NivOO5. Re-authored against current main
(stream_consumer.py is now ~4x larger than at #3412's branch base, with
new _NEW_SEGMENT/_COMMENTARY/finalize/_on_new_message machinery the
original PR didn't account for) but the design call (DM-only, edit-
fallback, transport=auto|draft|edit|off) is faithful to the original
proposal, with two improvements baked in:

  1. Per-response draft_id (monotonic counter, not a time hash) — no
     collision risk across consecutive responses on the same chat.
  2. Tool-boundary draft_id bump — prevents the inter-tool-call leak
     openclaw hit during their rollout (their #32535).

Closes #21439 (duplicate feature request).

gateway/run.py

@@ -13984,6 +13984,8 @@ class GatewayRunner:
                         cursor=_effective_cursor,
                         buffer_only=_buffer_only,
                         fresh_final_after_seconds=_fresh_final_secs,
+                        transport=_scfg.transport or "auto",
+                        chat_type=getattr(source, "chat_type", "") or "",
                     )
                     _stream_consumer = GatewayStreamConsumer(
                         adapter=_adapter,
@@ -14805,6 +14807,8 @@ class GatewayRunner:
                             cursor=_effective_cursor,
                             buffer_only=_buffer_only,
                             fresh_final_after_seconds=_fresh_final_secs,
+                            transport=_scfg.transport or "auto",
+                            chat_type=getattr(source, "chat_type", "") or "",
                         )
                         _stream_consumer = GatewayStreamConsumer(
                             adapter=_adapter,