fix(01-03): don't treat SIGTERM as crash, fix async callbacks in crash handler

- Only auto-restart on positive exit codes (genuine crashes), not negative
  return codes (signals like SIGTERM from our own process management)
- Add iscoroutinefunction check for on_error in crash handler max-retry path

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

telegram/claude_subprocess.py

@@ -230,8 +230,10 @@ class ClaudeSubprocess:
             returncode = await self._process.wait()
             logger.info(f"Claude Code process exited: returncode={returncode}")
 
-            # Handle crash (non-zero exit)
+            # Handle crash (non-zero exit, but not signals from our own termination)
-            if returncode != 0:
+            # Negative return codes are signals (e.g., -15 = SIGTERM, -9 = SIGKILL)
+            # Only auto-restart on genuine crashes (positive non-zero exit codes)
+            if returncode is not None and returncode > 0:
                 await self._handle_crash()
                 return
 
@@ -405,7 +407,10 @@ class ClaudeSubprocess:
             error_msg = f"Claude failed to restart after {self.MAX_CRASH_RETRIES} attempts"
             logger.error(error_msg)
             if self.on_error:
-                self.on_error(error_msg)
+                if inspect.iscoroutinefunction(self.on_error):
+                    asyncio.create_task(self.on_error(error_msg))
+                else:
+                    self.on_error(error_msg)
             self._crash_count = 0  # Reset for next session
             return