Add views, import/duplicate, DRC, jumps toggle, multi-wire select, auto-route, delete view tabs

- Roadmap #22: File→Import JSON to restore a diagram (drag-drop or file picker)
- Roadmap #23: Duplicate diagram from diagram list
- Roadmap #24: DRC panel with collapsible categories (unconnected pins, dup refs, no length, no P/N)
- Multi-view tabs: named views per diagram with independent device/wire layouts; snapshot-on-entry prevents bleed
- Keyboard arrow nudge for selected device(s)
- Undo for move, duplicate, label/property changes
- Wire jump arcs toggle (⌒ Jumps button in toolbar)
- Shift+click multi-wire selection; right-click bulk clear waypoints or auto-route
- Auto-route: obstacle-avoiding ortho routing for single or bulk selected wires
- Delete view tab with × button; right-click context menu for rename/delete

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

backend/app/routers/views.py

@@ -0,0 +1,77 @@
+from typing import List
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+from .. import models, schemas
+from ..database import get_db
+
+router = APIRouter(tags=["views"])
+
+
+@router.get("/diagram/{diagram_id}", response_model=List[schemas.DiagramViewOut])
+def list_views(diagram_id: int, db: Session = Depends(get_db)):
+    return db.query(models.DiagramView).filter(models.DiagramView.diagram_id == diagram_id).order_by(models.DiagramView.created_at).all()
+
+
+@router.post("/", response_model=schemas.DiagramViewOut, status_code=201)
+def create_view(payload: schemas.DiagramViewCreate, db: Session = Depends(get_db)):
+    view = models.DiagramView(**payload.model_dump())
+    db.add(view)
+    db.commit()
+    db.refresh(view)
+    return view
+
+
+@router.patch("/{view_id}", response_model=schemas.DiagramViewOut)
+def update_view(view_id: int, payload: schemas.DiagramViewUpdate, db: Session = Depends(get_db)):
+    view = db.get(models.DiagramView, view_id)
+    if not view:
+        raise HTTPException(404, "View not found")
+    for k, v in payload.model_dump(exclude_unset=True).items():
+        setattr(view, k, v)
+    db.commit()
+    db.refresh(view)
+    return view
+
+
+@router.delete("/{view_id}", status_code=204)
+def delete_view(view_id: int, db: Session = Depends(get_db)):
+    view = db.get(models.DiagramView, view_id)
+    if not view:
+        raise HTTPException(404, "View not found")
+    db.delete(view)
+    db.commit()
+
+
+@router.get("/{view_id}/layout", response_model=schemas.ViewLayout)
+def get_view_layout(view_id: int, db: Session = Depends(get_db)):
+    view = db.get(models.DiagramView, view_id)
+    if not view:
+        raise HTTPException(404, "View not found")
+    pos = {p.device_id: {"x": p.x, "y": p.y} for p in view.device_positions}
+    waypts = {w.wire_id: (w.waypoints or []) for w in view.wire_waypoints}
+    return {"device_positions": pos, "wire_waypoints": waypts}
+
+
+@router.patch("/{view_id}/devices/{device_id}")
+def update_view_device_position(view_id: int, device_id: int, payload: schemas.ViewDevicePositionUpdate, db: Session = Depends(get_db)):
+    pos = db.query(models.ViewDevicePosition).filter_by(view_id=view_id, device_id=device_id).first()
+    if pos:
+        pos.x = payload.x
+        pos.y = payload.y
+    else:
+        pos = models.ViewDevicePosition(view_id=view_id, device_id=device_id, x=payload.x, y=payload.y)
+        db.add(pos)
+    db.commit()
+    return {"ok": True}
+
+
+@router.patch("/{view_id}/wires/{wire_id}")
+def update_view_wire_waypoints(view_id: int, wire_id: int, payload: schemas.ViewWireWaypointsUpdate, db: Session = Depends(get_db)):
+    ww = db.query(models.ViewWireWaypoints).filter_by(view_id=view_id, wire_id=wire_id).first()
+    if ww:
+        ww.waypoints = payload.waypoints
+    else:
+        ww = models.ViewWireWaypoints(view_id=view_id, wire_id=wire_id, waypoints=payload.waypoints)
+        db.add(ww)
+    db.commit()
+    return {"ok": True}