fix: Save debug artifacts even when patch extraction fails

Helps debugging by preserving raw AI output when markers are missing.

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

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

automation/patcher.py

@@ -68,8 +68,13 @@ def generate_output(
 
         raw_path.write_text(raw_patch, encoding="utf-8")
 
+        try:
             extracted = extract_patch_with_markers(raw_path.read_text(encoding="utf-8"))
             clean_path.write_text(extracted, encoding="utf-8")
+        except PatchGenerationError as e:
+            # Save raw output even if extraction fails for debugging
+            save_debug_artifacts(repo_root, output_rel, raw_path, None, None, None)
+            raise
 
         sanitized = sanitize_unified_patch(clean_path.read_text(encoding="utf-8"))
         if "--- /dev/null" in sanitized and "new file mode" not in sanitized:
@@ -290,18 +295,21 @@ def rewrite_patch_for_p0(patch: str) -> str:
 def save_debug_artifacts(
     repo_root: Path,
     output_rel: Path,
-    raw_path: Path,
-    clean_path: Path,
-    sanitized_path: Path,
-    final_path: Path,
+    raw_path: Path | None,
+    clean_path: Path | None,
+    sanitized_path: Path | None,
+    final_path: Path | None,
 ) -> None:
     debug_dir = repo_root / ".git" / "ai-rules-debug"
     debug_dir.mkdir(parents=True, exist_ok=True)
     identifier = f"{output_rel.as_posix().replace('/', '_')}-{os.getpid()}"
+    if raw_path and raw_path.exists():
         shutil.copy(raw_path, debug_dir / f"{identifier}.raw.out")
+    if clean_path and clean_path.exists():
         shutil.copy(clean_path, debug_dir / f"{identifier}.clean.diff")
+    if sanitized_path and sanitized_path.exists():
         shutil.copy(sanitized_path, debug_dir / f"{identifier}.sanitized.diff")
-    if final_path.exists():
+    if final_path and final_path.exists():
         shutil.copy(final_path, debug_dir / f"{identifier}.final.diff")