fix(telegram): preserve incident history html output

apps/api/src/services/telegram_gateway.py

@@ -70,6 +70,7 @@ logger = structlog.get_logger(__name__)
 _TELEGRAM_BOT_URL_RE = re.compile(r"(api\.telegram\.org/bot)[^/\s]+")
 _INCIDENT_ID_RE = re.compile(r"\bINC-\d{8}-[A-Z0-9]{4,}\b")
 _CODE_REF_RE = re.compile(r"<code>([0-9a-f]{7,12})</code>", re.IGNORECASE)
+_TELEGRAM_HTML_CHUNK_LIMIT = 3600
 
 
 def _top_gateway_bucket(
@@ -195,6 +196,34 @@ def _format_remediation_history_lines(history: dict[str, object] | None) -> list
     ]
 
 
+def _telegram_html_chunks(lines: list[str], limit: int = _TELEGRAM_HTML_CHUNK_LIMIT) -> list[str]:
+    """Split HTML messages by complete lines so Telegram does not receive broken tags."""
+    chunks: list[str] = []
+    current: list[str] = []
+    current_len = 0
+    for raw_line in lines:
+        line = str(raw_line)
+        line_len = len(line) + 1
+        if current and current_len + line_len > limit:
+            chunks.append("\n".join(current))
+            current = []
+            current_len = 0
+        if line_len > limit:
+            chunks.append(line[:limit])
+            continue
+        current.append(line)
+        current_len += line_len
+    if current:
+        chunks.append("\n".join(current))
+    return chunks
+
+
+def _plain_text_from_html(text: str, limit: int = 3900) -> str:
+    """Fallback renderer for Telegram HTML parse failures."""
+    plain = re.sub(r"</?[^>]+>", "", text)
+    return html.unescape(plain)[:limit]
+
+
 def _sanitize_telegram_error(text: str) -> str:
     """遮蔽 Telegram Bot URL 中的 token，避免例外字串污染 log / trace。"""
     return _TELEGRAM_BOT_URL_RE.sub(r"\1<redacted>", text)
@@ -5366,7 +5395,10 @@ class TelegramGateway:
                     error=str(remediation_exc),
                 )
 
-            await self.send_notification("\n".join(lines))
+            await self._send_html_line_message(
+                lines,
+                failure_context="incident_detail",
+            )
 
         except Exception as e:
             logger.warning("send_incident_detail_failed", incident_id=incident_id, error=str(e))
@@ -5501,7 +5533,10 @@ class TelegramGateway:
                     error=str(truth_exc),
                 )
 
-            await self.send_notification("\n".join(lines))
+            await self._send_html_line_message(
+                lines,
+                failure_context="incident_history",
+            )
 
         except Exception as e:
             logger.warning("send_incident_history_failed", incident_id=incident_id, error=str(e))
@@ -5714,6 +5749,41 @@ class TelegramGateway:
 
         return await self._send_request("sendMessage", payload)
 
+    async def _send_html_line_message(
+        self,
+        lines: list[str],
+        *,
+        chat_id: str | int | None = None,
+        failure_context: str,
+    ) -> None:
+        """Send a multi-line HTML message without cutting Telegram tags in half."""
+        chunks = _telegram_html_chunks(lines)
+        for index, chunk in enumerate(chunks):
+            try:
+                await self._send_request(
+                    "sendMessage",
+                    {
+                        "chat_id": chat_id or self.alert_chat_id,
+                        "text": chunk,
+                        "parse_mode": "HTML",
+                    },
+                )
+            except Exception as exc:
+                logger.warning(
+                    "telegram_html_line_message_failed",
+                    failure_context=failure_context,
+                    chunk_index=index,
+                    chunk_count=len(chunks),
+                    error=str(exc),
+                )
+                await self._send_request(
+                    "sendMessage",
+                    {
+                        "chat_id": chat_id or self.alert_chat_id,
+                        "text": _plain_text_from_html(chunk),
+                    },
+                )
+
     async def send_alert_notification(
         self,
         text: str,