fix(telemetry): INSERT OR IGNORE + WAL + try/except 三层防御加固

根治遥测写入主键冲突(UNIQUE constraint)和并发写锁(database is locked)
导致的异常冒泡，遥测侧信道错误不再污染 LLM 重试链。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

adapters/telemetry.py

@@ -10,6 +10,8 @@ import asyncio
 import sqlite3
 from typing import TYPE_CHECKING
 
+from loguru import logger
+
 if TYPE_CHECKING:
     from pathlib import Path
 
@@ -45,7 +47,7 @@ class SQLiteTelemetryRecorder:
     """
 
     _INSERT_SQL = """
-    INSERT INTO llm_calls (
+    INSERT OR IGNORE INTO llm_calls (
         call_id, parent_call_id, session_id,
         model_name, provider, messages, response, thinking,
         prompt_tokens, completion_tokens, latency_ms,
@@ -85,33 +87,46 @@ class SQLiteTelemetryRecorder:
         cache_hit: bool,
         error: str | None,
     ) -> None:
-        """同步写入一条 LLM 调用记录到 SQLite。"""
-        conn = sqlite3.connect(str(self._db_path))
+        """同步写入一条 LLM 调用记录到 SQLite。
+
+        三层防御加固：
+        1. INSERT OR IGNORE — 主键冲突静默忽略
+        2. WAL + busy_timeout — 并发写锁容忍
+        3. try/except sqlite3.Error — DB 错误不冒泡到调用方
+        """
         try:
-            self._ensure_table(conn)
-            conn.execute(
-                self._INSERT_SQL,
-                (
-                    call_id,
-                    parent_call_id,
-                    session_id,
-                    model_name,
-                    provider,
-                    messages,
-                    response,
-                    thinking,
-                    prompt_tokens,
-                    completion_tokens,
-                    latency_ms,
-                    ttft_ms,
-                    max_inter_token_ms,
-                    int(cache_hit),
-                    error,
-                ),
+            conn = sqlite3.connect(str(self._db_path), timeout=10.0)
+            try:
+                conn.execute("PRAGMA journal_mode=WAL")
+                conn.execute("PRAGMA busy_timeout=5000")
+                self._ensure_table(conn)
+                conn.execute(
+                    self._INSERT_SQL,
+                    (
+                        call_id,
+                        parent_call_id,
+                        session_id,
+                        model_name,
+                        provider,
+                        messages,
+                        response,
+                        thinking,
+                        prompt_tokens,
+                        completion_tokens,
+                        latency_ms,
+                        ttft_ms,
+                        max_inter_token_ms,
+                        int(cache_hit),
+                        error,
+                    ),
+                )
+                conn.commit()
+            finally:
+                conn.close()
+        except sqlite3.Error as exc:
+            logger.warning(
+                "遥测写入失败（已降级），call_id={}: {}", call_id, exc
             )
-            conn.commit()
-        finally:
-            conn.close()
 
     async def record_llm_call(
         self,