Scope git commit to current diagram + fix complete JSON export/import

- Git commit: "Current diagram only" checkbox stages only that diagram's
  JSON file instead of all diagrams
- JSON export now includes: waypoints, twisted_pair, twist_pitch, shielded,
  show_size_label, bundle_id, bundle_label, sheet_id, sheets, wire_bundles
- JSON import reconstructs sheets and bundles with remapped IDs so restored
  diagrams are exact copies

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/routers/diagrams.py

@@ -119,10 +119,38 @@ async def import_diagram(request: Request, db: Session = Depends(get_db)):
     db.add(new_diag)
     db.flush()
 
-    id_map = {}
+    # Sheets: old id → new Sheet object
+    sheet_map = {}
+    for s in data.get("sheets", []):
+        ns = models.Sheet(
+            diagram_id=new_diag.id,
+            name=s.get("name", "Sheet 1"),
+            position=s.get("position", 0),
+        )
+        db.add(ns)
+        db.flush()
+        if "id" in s:
+            sheet_map[s["id"]] = ns.id
+
+    # Wire bundles: old id → new bundle id
+    bundle_map = {}
+    for b in data.get("wire_bundles", []):
+        nb = models.WireBundle(
+            diagram_id=new_diag.id,
+            label=b.get("label", ""),
+            jacket_color=b.get("jacket_color", "#2a2a2a"),
+        )
+        db.add(nb)
+        db.flush()
+        if "id" in b:
+            bundle_map[b["id"]] = nb.id
+
+    # Devices: old id → new device id
+    dev_map = {}
     for dev_data in data.get("devices", []):
         new_dev = models.Device(
             diagram_id=new_diag.id,
+            sheet_id=sheet_map.get(dev_data.get("sheet_id")),
             device_type=dev_data.get("device_type", "generic"),
             label=dev_data.get("label", ""),
             reference=dev_data.get("reference", ""),
@@ -136,15 +164,16 @@ async def import_diagram(request: Request, db: Session = Depends(get_db)):
         db.add(new_dev)
         db.flush()
         if "id" in dev_data:
-            id_map[dev_data["id"]] = new_dev.id
+            dev_map[dev_data["id"]] = new_dev.id
 
     for wire_data in data.get("wires", []):
         new_wire = models.Wire(
             diagram_id=new_diag.id,
+            sheet_id=sheet_map.get(wire_data.get("sheet_id")),
             label=wire_data.get("label", ""),
-            from_device_id=id_map.get(wire_data.get("from_device_id")),
+            from_device_id=dev_map.get(wire_data.get("from_device_id")),
             from_pin=wire_data.get("from_pin", ""),
-            to_device_id=id_map.get(wire_data.get("to_device_id")),
+            to_device_id=dev_map.get(wire_data.get("to_device_id")),
             to_pin=wire_data.get("to_pin", ""),
             color_primary=wire_data.get("color_primary", "#FF0000"),
             color_stripe=wire_data.get("color_stripe"),
@@ -157,6 +186,7 @@ async def import_diagram(request: Request, db: Session = Depends(get_db)):
             twist_pitch=wire_data.get("twist_pitch", 16.0),
             shielded=wire_data.get("shielded", False),
             show_size_label=wire_data.get("show_size_label", False),
+            bundle_id=bundle_map.get(wire_data.get("bundle_id")),
         )
         db.add(new_wire)