fix(audience): convert remaining setConsent comparisons + fix mock

Convert the 3 remaining raw consent string comparisons in sdk.ts
setConsent() to use the capability functions:

- level === 'none' (queue stop)    → !canTrack(level)
- level === 'none' (cookie delete) → !canTrack(level)
- level === 'anonymous' && previous === 'full' (userId clear)
  → canIdentify(previous) && !canIdentify(level)

These were left as raw comparisons in the initial refactor because
they're state transitions, but they gate the same capabilities as the
query functions. If a future consent level blocks tracking (like
'none' does), these would silently diverge without this change.

Also fix canTrack mock in pixel.test.ts from a bare arrow to
jest.fn().mockImplementation() so it can be overridden per-test.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ImmutableJeffrey

packages/audience/pixel/src/pixel.test.ts

@@ -72,7 +72,7 @@ jest.mock('@imtbl/audience-core', () => ({
       };
     },
   ),
-  canTrack: (level: string) => level !== 'none',
+  canTrack: jest.fn().mockImplementation((level: string) => level !== 'none'),
 }));
 
 // Mock fetch globally

packages/audience/sdk/src/sdk.ts

@@ -362,7 +362,7 @@ export class Audience {
 
     // Web-specific cleanup before core handles queue purge/transform and server sync.
     // session_end is intentionally not emitted — no events should be sent after opt-out.
-    if (level === 'none') {
+    if (!canTrack(level)) {
       this.queue.stop();
     }
 
@@ -371,10 +371,10 @@ export class Audience {
     this.consent.setLevel(level);
 
     // Web-specific cleanup after core's transition.
-    if (level === 'none') {
+    if (!canTrack(level)) {
       deleteCookie(COOKIE_NAME, this.cookieDomain);
       deleteCookie(SESSION_COOKIE, this.cookieDomain);
-    } else if (level === 'anonymous' && previous === 'full') {
+    } else if (canIdentify(previous) && !canIdentify(level)) {
       this.userId = undefined;
     }