feat: auto-sync file list + clear processing cache

- Auto-sync file_relations on every query (files appear immediately)
- Add POST /api/files/reset-cache endpoint to delete output/result
  files and reset status to pending for reprocessing
- Add "清除处理缓存" button to all 3 file views

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/backend/routers/files.py

@@ -15,7 +15,7 @@ from ..config import MAX_UPLOAD_SIZE, ALLOWED_EXTENSIONS
 from ..services.db_schema import (
     insert_file_metadata, query_file_history, query_file_stats,
     query_file_relations, delete_file_relations, sync_file_relations,
-    query_file_relations_stats,
+    query_file_relations_stats, reset_file_cache,
 )
 
 logger = logging.getLogger(__name__)
@@ -301,9 +301,12 @@ async def get_file_relations(
     page_size: int = Query(50, ge=1, le=200),
     sort_by: Optional[str] = None,
     sort_order: str = "desc",
+    sync: bool = Query(True, description="Auto-sync file relations before querying"),
     current_user: dict = Depends(get_current_user),
 ):
     """Query file relations with optional view filter."""
+    if sync:
+        sync_file_relations()
     items, total = query_file_relations(view=view, status=status, page=page, page_size=page_size,
                                         sort_by=sort_by, sort_order=sort_order)
     return {"items": items, "total": total}
@@ -326,6 +329,24 @@ async def sync_relations(
     return {"message": "文件关系表已重建"}
 
 
+class ResetCacheRequest(BaseModel):
+    files: list[dict]  # [{input_image, output_excel, result_purchase}, ...]
+
+
+@router.post("/reset-cache")
+async def reset_cache(
+    req: ResetCacheRequest,
+    current_user: dict = Depends(get_current_user),
+):
+    """Delete output/result files and reset status to pending for reprocessing.
+
+    Each item in files should have: {input_image?, output_excel?, result_purchase?}
+    The corresponding files on disk are deleted, and the relation status is reset.
+    """
+    result = reset_file_cache(req.files)
+    return result
+
+
 @router.delete("/relations")
 async def delete_relations(
     body: RelationDeleteRequest,

web/backend/services/db_schema.py

@@ -653,6 +653,71 @@ def sync_file_relations():
         conn.close()
 
 
+def reset_file_cache(files: list[dict]) -> dict:
+    """Delete output/result files and reset relation status to pending.
+
+    Each item: {input_image?, output_excel?, result_purchase?}
+    Deletes the corresponding files from disk and resets status.
+    """
+    project_root = Path(__file__).resolve().parent.parent.parent.parent
+    output_dir = project_root / 'data' / 'output'
+    result_dir = project_root / 'data' / 'result'
+
+    deleted_files = 0
+    reset_count = 0
+    errors = []
+
+    conn = sqlite3.connect(_db_path)
+    conn.row_factory = sqlite3.Row
+    try:
+        for item in files:
+            input_image = item.get('input_image')
+            output_excel = item.get('output_excel')
+            result_purchase = item.get('result_purchase')
+
+            # Delete output file from disk
+            if output_excel:
+                out_path = output_dir / output_excel
+                if out_path.exists():
+                    try:
+                        out_path.unlink()
+                        deleted_files += 1
+                    except Exception as e:
+                        errors.append(f"{output_excel}: {e}")
+
+            # Delete result file from disk
+            if result_purchase:
+                res_path = result_dir / result_purchase
+                if res_path.exists():
+                    try:
+                        res_path.unlink()
+                        deleted_files += 1
+                    except Exception as e:
+                        errors.append(f"{result_purchase}: {e}")
+
+            # Reset relation status to pending
+            if input_image:
+                conn.execute(
+                    "UPDATE file_relations SET output_excel = NULL, result_purchase = NULL, "
+                    "status = 'pending', updated_at = ? WHERE input_image = ?",
+                    (datetime.now().isoformat(), input_image),
+                )
+                reset_count += conn.total_changes
+            elif output_excel:
+                conn.execute(
+                    "UPDATE file_relations SET output_excel = NULL, result_purchase = NULL, "
+                    "status = 'pending', updated_at = ? WHERE output_excel = ?",
+                    (datetime.now().isoformat(), output_excel),
+                )
+                reset_count += conn.total_changes
+
+        conn.commit()
+    finally:
+        conn.close()
+
+    return {"deleted_files": deleted_files, "reset_relations": reset_count, "errors": errors}
+
+
 def query_file_relations_stats() -> dict:
     """Get detailed file statistics for Dashboard.