Fix duplicate-index crash in data validation, add Telegram flood control

- Move index dedup before OHLC consistency fix in _validate_and_clean
  to prevent crash when df.loc[dup_idx] returns Series instead of scalar
- Add global flood backoff: detect RetryAfter, pause all sends/edits
  until ban expires instead of retrying and escalating the ban
- Stop dashboard edit-fail → new-message spam cascade: track consecutive
  failures, only resend after 3 failed edits
- Increase dashboard refresh from 5s to 30s, min send interval to 1.5s
- Add comprehensive QA test suite (140 tests across all 7 modules)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

telegram_bot.py

@@ -131,15 +131,32 @@ AUTOSCAN_CONFIRMATIONS = {
 
 _executor = ThreadPoolExecutor(max_workers=4)
 
-# ── Telegram rate limiter (1 msg/sec per chat) ────────────────────────
+# ── Telegram rate limiter with flood control ─────────────────────────
 
 _send_lock = asyncio.Lock()
 _last_send_per_chat: Dict[int, float] = {}
-_TELEGRAM_MIN_INTERVAL = 1.0
+_TELEGRAM_MIN_INTERVAL = 1.5
 _TELEGRAM_SEND_TIMEOUT = 30
+_flood_until: float = 0.0
+
+
+def _is_flood_blocked() -> bool:
+    return time.time() < _flood_until
+
+
+def _handle_retry_after(retry_seconds: int) -> None:
+    global _flood_until
+    _flood_until = time.time() + retry_seconds
+    logger.warning(
+        f"Telegram flood control: pausing ALL sends for {retry_seconds}s "
+        f"(until {datetime.fromtimestamp(_flood_until, tz=timezone.utc).strftime('%H:%M:%S UTC')})"
+    )
 
 
 async def _rate_limited_send(bot, chat_id: int, text: str, **kwargs) -> Optional[object]:
+    if _is_flood_blocked():
+        logger.debug(f"Send skipped — flood backoff active ({_flood_until - time.time():.0f}s left)")
+        return None
     async with _send_lock:
         now = time.time()
         last = _last_send_per_chat.get(chat_id, 0)
@@ -156,12 +173,17 @@ async def _rate_limited_send(bot, chat_id: int, text: str, **kwargs) -> Optional
         except asyncio.TimeoutError:
             logger.error(f"Telegram send_message timed out for chat {chat_id}")
             return None
-        except Exception:
-            logger.exception(f"Telegram send_message failed for chat {chat_id}")
+        except Exception as exc:
+            if "retry" in str(exc).lower() and hasattr(exc, "retry_after"):
+                _handle_retry_after(int(exc.retry_after))
+            else:
+                logger.exception(f"Telegram send_message failed for chat {chat_id}")
             return None
 
 
 async def _rate_limited_edit(bot, text: str, chat_id: int, message_id: int, **kwargs) -> bool:
+    if _is_flood_blocked():
+        return False
     try:
         await asyncio.wait_for(
             bot.edit_message_text(text, chat_id=chat_id, message_id=message_id, **kwargs),
@@ -172,6 +194,9 @@ async def _rate_limited_edit(bot, text: str, chat_id: int, message_id: int, **kw
         logger.error(f"Telegram edit_message timed out for chat {chat_id}")
         return False
     except Exception as exc:
+        if "retry" in str(exc).lower() and hasattr(exc, "retry_after"):
+            _handle_retry_after(int(exc.retry_after))
+            return False
         if "message is not modified" not in str(exc).lower():
             logger.warning(f"Telegram edit_message failed for chat {chat_id}: {exc}")
         return False
@@ -445,19 +470,27 @@ def _format_stats_dashboard() -> str:
 _dashboard_msg_ids: Dict[int, int] = {}
 _dashboard_task: Optional[asyncio.Task] = None
 _last_dashboard_refresh: float = 0
-_DASHBOARD_THROTTLE = 5
+_DASHBOARD_THROTTLE = 30
+_DASHBOARD_LOOP_INTERVAL = 30
 _dashboard_lock = asyncio.Lock()
+_dashboard_edit_failures: Dict[int, int] = {}
+_DASHBOARD_MAX_EDIT_FAILURES = 3
 
 
 async def _send_dashboard(bot, chat_id: int) -> None:
+    if _is_flood_blocked():
+        return
     text = _format_stats_dashboard()
     msg = await _rate_limited_send(bot, chat_id, text, parse_mode=ParseMode.MARKDOWN)
     if msg:
         _dashboard_msg_ids[chat_id] = msg.message_id
+        _dashboard_edit_failures[chat_id] = 0
 
 
 async def _refresh_dashboard(bot, force: bool = False) -> None:
     global _last_dashboard_refresh
+    if _is_flood_blocked():
+        return
     async with _dashboard_lock:
         now = time.time()
         if not force and (now - _last_dashboard_refresh) < _DASHBOARD_THROTTLE:
@@ -475,13 +508,20 @@ async def _refresh_dashboard(bot, force: bool = False) -> None:
                 parse_mode=ParseMode.MARKDOWN,
             )
             if not ok:
-                await _send_dashboard(bot, chat_id)
+                failures = _dashboard_edit_failures.get(chat_id, 0) + 1
+                _dashboard_edit_failures[chat_id] = failures
+                if failures >= _DASHBOARD_MAX_EDIT_FAILURES:
+                    logger.info(f"Dashboard edit failed {failures}x for chat {chat_id}, sending new message")
+                    _dashboard_edit_failures[chat_id] = 0
+                    await _send_dashboard(bot, chat_id)
+            else:
+                _dashboard_edit_failures[chat_id] = 0
 
 
 async def _dashboard_loop(bot) -> None:
     try:
         while _autoscan_chats:
-            await asyncio.sleep(5)
+            await asyncio.sleep(_DASHBOARD_LOOP_INTERVAL)
             if not _autoscan_chats:
                 break
             await _refresh_dashboard(bot)