fix: harden bounded state sidecars

N-05: the conditional-validator key was a colon join over components that may
themselves contain colons, so two distinct valid bindings could collide and one
definition's ETag could be prepared for another. The key is now a validated,
byte-bounded fixed tuple encoded with JSON.stringify.

N-09: capture localStorage exactly once and compare StorageEvent.storageArea
against that object identity, so a pulse from sessionStorage or any other area
is rejected instead of matching on key and value alone. The pulse key is
registered in the storage registry as CACHE_INVALIDATION_PULSE.

N-10: race loadPage against the caller signal and re-check before observing a
page, so a non-cooperative loader can neither hold loadAll forever nor have a
post-abort completion accumulated into a successful result.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/unit/conditional-validator-store.test.ts

@@ -44,6 +44,31 @@ describe("conditional validator CAS sidecar", () => {
     expect(store.acceptNotModified(binding, 7, true)).toBe(false);
   });
 
+  it("keeps colon-bearing validator tuples injective", () => {
+    const selectedScope = scope();
+    // N-05. Both bindings are individually valid and, under a delimiter join,
+    // encode to the same key.
+    const first = {
+      definitionId: "resource:detail",
+      identityToken: "identity-token-00000001",
+      representationVersion: 1,
+      scope: selectedScope.snapshot,
+    };
+    const second = {
+      definitionId: "resource",
+      identityToken: "detail:identity-token-00000001",
+      representationVersion: 1,
+      scope: selectedScope.snapshot,
+    };
+    const store = createConditionalValidatorStore();
+
+    expect(store.install(first, '"etag-a"', 7)).toBe(true);
+    expect(store.install(second, '"etag-b"', 7)).toBe(true);
+
+    expect(store.prepare(first, 7)).toBe('"etag-a"');
+    expect(store.prepare(second, 7)).toBe('"etag-b"');
+  });
+
   it("rejects malformed validators and bounded-capacity overflow", () => {
     const firstScope = scope();
     const store = createConditionalValidatorStore(1);