…Bot v2 API

… attempts

Fix 4 issues in QQBot adapter reconnect logic:

1. [P0] _listen_loop exit now calls _set_fatal_error() to notify Gateway
   When reconnect attempts are exhausted, the adapter now sets a retryable
   fatal error so _platform_reconnect_watcher can take over. Previously
   the listen loop would silently die, leaving QQBot in a zombie state
   where the process is alive but no messages are received.

2. [P1] CLOSED/ERROR WS events now raise QQCloseError instead of plain
   RuntimeError, preserving close code/reason for proper error classification.

3. [P1] Added 15s cooldown after reconnect failure to give QQ server time
   to clean up the old session before the next attempt.

4. [P2] Moved _heartbeat_interval reset inside _reconnect() try block
   so it only resets after a successful connection, not on failure.

…t-fix

…a support)

Keep both QQBot and Feishu native media delivery blocks. Preserve
QQBot's full chat_type routing and base64 file upload logic from
HEAD, while incorporating Feishu's media support and thread_id
parameter from upstream/main. Update error/warning strings to
list both platforms.

…t-fix

…t-fix

…ping/pong

Bug 5: _reconnect() opens a new WebSocket but never recreates _heartbeat_task.
The old heartbeat task is orphaned on the dead connection — no heartbeat is
sent on the new one. QQ server closes the connection after 60s with code=None
(no close code because the server drops it cleanly). Reconnect succeeds,
but the death loop repeats every 60s: connect → 60s silence → disconnect
→ reconnect → repeat.

Changes:
- _open_ws(): add heartbeat=20 to aiohttp ClientWebSocketResponse for
  WS-level ping/pong, preventing idle disconnects at the transport layer
- _reconnect(): cancel old _heartbeat_task before opening new WebSocket
- _reconnect(): create_task(_heartbeat_loop()) after successful reconnect

MEDIA: tag extraction silently ignored .md, .json, .xml, .html, .log,
.yaml, .yml, and .toml files because the extension allowlist in
BasePlatformAdapter.extract_media() didn't include these formats.

This prevented the gateway's _deliver_media_tags_streaming() and the
send_message tool from delivering document files produce d by agents
(e.g. markdown reports, logs, config files) via QQBot and other
platforms that use send_document().

Fix: add md|json|xml|html?|log|yaml|yml|toml to the regex extension
alternation.  All 183 existing tests pass with no regressions.

Verified:
  - MEDIA:/path/to/file.md  → extracted correctly
  - MEDIA:/path/to/file.json → extracted correctly
  - Existing formats (pdf, docx, png, etc.) → no regression