feat(collab): selection soft-locks — remote-selected items can't be dragged locally (collab-presence 0007)

While a peer has an item selected, local users can still select it for
inspection but move/drag/rotate/delete skip it with an infobar naming the
holder (native locked-item UX; enforced via the fork's PCBJAM_REMOTE_LOCK
query — kicad 81f9cd80fd, the epic's first fork-touching phase). Overlapping
holds (both grabbed inside the awareness propagation window) tie-break
deterministically: lowest (user.id, clientID) keeps the item, every losing
client auto-releases it.

- lock-tiebreak.ts: pure policy — beats(), remoteLocks() (union of ALL other
  clients' selections incl. own user's other tabs, minus own-held-and-winning
  uuids so the winner isn't blocked mid-release), contestedReleases()
- presence.ts: clients() (per-client view, no user dedupe) + self(); FIX for
  a pre-existing flaky stack overflow — resolveCollision re-entered itself
  synchronously via its own patch's awareness 'change' and could ping-pong on
  stale same-user states (~1-in-3 unit runs); re-entrancy guard defers
  re-resolution to the next genuine delivery
- presence-kicad.ts: locks ride the kicadCollabSetRemote snapshot
  (`locks:[{uuid,name}]`); losing overlaps call kicadCollabReleaseSelection
- wasm bindings (both TUs + merged dispatch): g_locks map + fork query
  install; kicadCollabReleaseSelection (cancelInteractive only when a tool
  stack is live — bare ESC would clear the whole selection — then selective
  RemoveItemFromSel + infobar + forced re-emit); kicadCollabTestGetLocked
- tests: lock-tiebreak unit suite; presence-locks e2e for both editors (real
  move veto — pcbnew click+M hotkey since its default left-drag is
  rubber-band select, eeschema real drag — each with an unlocked control);
  two-tab tests/web/locks.spec.ts (lock propagation + deterministic tiebreak
  release + unlock on clear, passing vs real partykit)

Spec: docs/features/collab-presence/0007 (closed repo).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lg5jwWuhFH5dL8hEcBDuP2

wasm/bindings/kicad_editor_embind.cpp

@@ -59,6 +59,9 @@ std::string pcbCollabGetSelection();
 std::string pcbCollabGetSelectionFull();
 std::string pcbCollabTestGetCrossMapped();
 std::string pcbCollabTestSelectComponent();
+// Selection soft-locks (collab-presence 0007).
+void        pcbCollabReleaseSelection( std::string aUuidsJson, std::string aHolder );
+std::string pcbCollabTestGetLocked();
 std::string pcbCollabTestSelectFirst();
 bool        pcbCollabTestClearSelection();
 
@@ -85,6 +88,9 @@ std::string schCollabGetSelection();
 std::string schCollabGetSelectionFull();
 std::string schCollabTestGetCrossMapped();
 std::string schCollabTestSelectComponent();
+// Selection soft-locks (collab-presence 0007).
+void        schCollabReleaseSelection( std::string aUuidsJson, std::string aHolder );
+std::string schCollabTestGetLocked();
 std::string schCollabTestSelectFirst();
 bool        schCollabTestClearSelection();
 
@@ -227,6 +233,17 @@ static std::string collabTestSelectComponent()
     return pcbEditorActive() ? pcbCollabTestSelectComponent() : schCollabTestSelectComponent();
 }
 
+static void collabReleaseSelection( std::string aUuidsJson, std::string aHolder )
+{
+    pcbEditorActive() ? pcbCollabReleaseSelection( aUuidsJson, aHolder )
+                      : schCollabReleaseSelection( aUuidsJson, aHolder );
+}
+
+static std::string collabTestGetLocked()
+{
+    return pcbEditorActive() ? pcbCollabTestGetLocked() : schCollabTestGetLocked();
+}
+
 static std::string collabTestSelectFirst()
 {
     return pcbEditorActive() ? pcbCollabTestSelectFirst() : schCollabTestSelectFirst();
@@ -268,6 +285,9 @@ EMSCRIPTEN_BINDINGS(kicad_editor) {
     function("kicadCollabGetSelectionFull", &collabGetSelectionFull);
     function("kicadCollabTestGetCrossMapped", &collabTestGetCrossMapped);
     function("kicadCollabTestSelectComponent", &collabTestSelectComponent);
+    // Selection soft-locks (collab-presence 0007).
+    function("kicadCollabReleaseSelection", &collabReleaseSelection);
+    function("kicadCollabTestGetLocked", &collabTestGetLocked);
     function("kicadCollabTestSelectFirst", &collabTestSelectFirst);
     function("kicadCollabTestClearSelection", &collabTestClearSelection);
 }