Optimize topology canvas per the 2026-10-12 plan.

Save path: one atomic POST /views/{id}/commit (edges, ports, styles, node
add/remove, positions) replaces the multi-request save. Edge styles and
manual-edge port edits now go through dirty/undo/save instead of writing
immediately; non-manual edge ports are read-only.

Data safety: UI saves no longer clear MCP node locks or freeze the device
name into the placement label (label_override + omit-means-keep semantics,
also applied to the MCP positions tool). Adding NEs/neighbors with unsaved
edits now saves first instead of silently dropping them. Positions no longer
bypass membership caps, except persisting synthesized child-region icons.

Fixes found in acceptance: nodes added in the same commit kept (40,40)
under autoflush=False; edits on edges deleted in the same save 404'd the
whole save; box-selection drags and arrow-key moves were not marked dirty;
large canvases far from the origin opened blank and locate did nothing
because fitView waits for measurement that onlyRenderVisibleElements never
does (now fitBounds from known geometry).

Also: batch N+1 lookups in graph/positions, deterministic truncation,
outside-peer scan excludes internal edges, split TopologyPage into hooks,
fix flaky UME/LLDP port test, add scripts/topology_clear_frozen_labels.py.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/topology_clear_frozen_labels.py

@@ -0,0 +1,79 @@
+"""Clear view-node labels that merely freeze the current fabric name/ip.
+
+Default is dry-run. Pass --apply to write.
+
+A placement label is considered frozen when it equals the fabric node's current
+name or IP (case-insensitive, stripped). Clearing it restores follow-device-name
+behavior on the next graph read.
+"""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+from sqlalchemy import or_
+
+from netx_api.db import SessionLocal
+from netx_api.models import TopoFabricNode, TopoViewNode
+
+
+def _norm(s: str | None) -> str:
+    return str(s or "").strip().casefold()
+
+
+def clear_frozen_labels(db, *, apply: bool) -> tuple[int, int]:
+    """Return (scanned_nonempty_labels, frozen_cleared). Caller commits/rolls back."""
+    rows = (
+        db.query(TopoViewNode, TopoFabricNode)
+        .outerjoin(TopoFabricNode, TopoFabricNode.id == TopoViewNode.fabric_node_id)
+        .filter(TopoViewNode.label != "")
+        .filter(or_(TopoViewNode.label.isnot(None)))
+        .all()
+    )
+    scanned = 0
+    cleared = 0
+    for vn, fn in rows:
+        scanned += 1
+        label = _norm(vn.label)
+        if not label or fn is None:
+            continue
+        if label not in {_norm(fn.name), _norm(fn.ip)}:
+            continue
+        cleared += 1
+        if apply:
+            vn.label = ""
+    return scanned, cleared
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "--apply",
+        action="store_true",
+        help="Write changes (default: dry-run only)",
+    )
+    args = parser.parse_args(argv)
+
+    db = SessionLocal()
+    try:
+        scanned, cleared = clear_frozen_labels(db, apply=args.apply)
+        if args.apply:
+            db.commit()
+        else:
+            db.rollback()
+        mode = "apply" if args.apply else "dry-run"
+        print(f"mode={mode} scanned={scanned} frozen_labels={cleared}")
+        return 0
+    except Exception:
+        db.rollback()
+        raise
+    finally:
+        db.close()
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())