Persist capture data per session (field values, schema, links)

Capture mode state lived only in React memory and was lost when
reopening a session or remounting EngineProvider.

- Add per-session localStorage capture snapshot (schema, values, links)
- Restore on session mount; persist on field/schema/link changes
- Seed binder links from storage without spurious bus events
- Clean up capture key when session is deleted
- Integration test for reload persistence

src/binder/BinderProvider.tsx

@@ -20,6 +20,8 @@ import {
   type ReactNode,
 } from "react";
 
+import type { EvidenceLink } from "@shared/evidence-link";
+
 import type { EventBus } from "@engine/events";
 
 import {
@@ -68,9 +70,20 @@ export interface BinderProviderProps {
    * because its observers attach to the current `window`.
    */
   readonly services?: Omit<BinderServices, "rect">;
+  /**
+   * Restored evidence links for this session. Seeded directly into the
+   * repo (no bus events) so reload does not spuriously re-emit
+   * `EvidenceLinkCreated`.
+   */
+  readonly initialLinks?: readonly EvidenceLink[];
 }
 
-export function BinderProvider({ children, bus, services }: BinderProviderProps) {
+export function BinderProvider({
+  children,
+  bus,
+  services,
+  initialLinks,
+}: BinderProviderProps) {
   const built = useMemo<BinderServices>(() => {
     const links = services?.links ?? createInMemoryLinkRepo();
     const bindings = services?.bindings ?? createBindingService(links, bus);
@@ -78,6 +91,15 @@ export function BinderProvider({ children, bus, services }: BinderProviderProps)
     return { links, bindings, rect };
   }, [bus, services]);
 
+  useEffect(() => {
+    if (!initialLinks?.length || services?.links) return;
+    for (const link of initialLinks) {
+      if (!built.links.get(link.id)) {
+        built.links.create(link);
+      }
+    }
+  }, [built.links, initialLinks, services?.links]);
+
   // Disconnect rect observers + listeners on unmount.
   useEffect(() => {
     return () => {