CE-WP-0006/0007: Capture view polish, workplans, and UX refinements

- Blob URL stability, scroll centre, strip-only visual guide
- Focus-gated linking, unlink clears overlay, field badge tooltips
- Capture layout (viewer centre), grey guide lines, Add field button
- Workplans CE-WP-0006 (done) and CE-WP-0007 (T01-T09 done, T10-T12 todo)
- Integration tests and viewer-url helpers

src/binder/services/bindings.ts

@@ -76,7 +76,11 @@ export function createBindingService(
       return stored;
     },
     unlinkEvidence(id) {
-      return links.delete(id);
+      const removed = links.delete(id);
+      if (removed) {
+        bus.emit({ type: "EvidenceLinkRemoved", linkId: id });
+      }
+      return removed;
     },
     updateLink(id, input) {
       const existing = links.get(id);