fix: resolve Vitest TDZ on NiceNavigationItemRef initialization

[gabrielroberge]

Summary

Fixes a ReferenceError: Cannot access 'NiceNavigationItemRef' before initialization occurring under Vitest when a consumer project loads the package TypeScript sources through sourcemaps. ng serve / ng build were not impacted.

Problem

Two combined causes in the navigation module graph:

1. TDZ in NiceNavigationItemsRenderer

Signal field initializers access NiceNavigationItemRef during class evaluation:

contentChildren(NiceNavigationItemRef, …)
inject(NiceNavigationItemRef, …)

Angular metadata already used forwardRef, but the compiled field initializers did not.

2. Runtime import cycle

navigation-items.ts → navigation-item-ref.ts → navigation.ts → navigation-items.ts

Changes

navigation-items.ts

• Added forwardRef to contentChildren and inject.

navigation-item-ref.ts

• Replaced the NiceNavigation runtime import with NiceNavigationItemsRenderer.
• Added forwardRef to inject to break the runtime cycle down to 3 files.

Impact

• No public API changes.
• No regression on ng serve / ng build.

Note:

This bug is not reproducible through ng test inside the library itself because @angular/build:unit-test bundles all sources into a single Vite chunk, masking the ESM initialization-order issue.