Add /api/admin/reset/{section} endpoint for Danger Zone reset

backend/main.py

@@ -1928,6 +1928,28 @@ async def restore_backup(
     shutil.copy2(fp, src)
     return {"restored": filename, "auto_backup": auto_dst.name if src.exists() else None}
 
+
+@app.post("/api/admin/reset/{section}")
+async def reset_section(
+    section: str,
+    current_user: User = Depends(get_current_admin),
+):
+    """Reset (truncate) a specific data section. Creates auto-backup first."""
+    valid = {"attendance": AttendanceRecord, "holidays": Holiday, "leaves": LeaveRecord}
+    if section not in valid:
+        raise HTTPException(status_code=400, detail=f"Unknown section: {section}")
+    # Auto-backup before reset
+    src = Path(DB_PATH)
+    if src.exists():
+        auto_dst = _backup_path(f"auto_pre_{section}_reset")
+        shutil.copy2(src, auto_dst)
+    # Truncate table
+    model = valid[section]
+    db.execute(model.__table__.delete())
+    db.commit()
+    return {"reset": section, "auto_backup": auto_dst.name}
+
+
 @app.get("/api/version")
 async def get_version(
     current_user: User = Depends(get_current_user),