fix: Handle claude CLI exit code 1 for successful responses

Claude CLI returns exit code 1 even when successfully generating output.
Check for stdout content before failing on non-zero exit codes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

automation/patcher.py

@@ -224,6 +224,12 @@ def call_model(model: ModelConfig, prompt: str, cwd: Path) -> str:
         cwd=str(cwd),
         shell=True,
     )
+    # Check if we got output even if returncode is non-zero
+    # (claude CLI returns 1 even on successful prompt responses)
+    if result.stdout.strip():
+        return result.stdout
+
+    # Only raise error if we got nothing useful
     if result.returncode != 0:
         raise PatchGenerationError(f"AI command failed ({result.returncode}): {result.stderr.strip()}")
     return result.stdout