Fix page build regression from service worker WASM asset injection

[Copilot]

The last web change broke the website by producing an invalid generated service worker during the page build. The breakage came from the asset cache list no longer remaining syntactically valid after the build step injected the hashed WASM filename.

• Service worker asset list

  • Add the missing trailing comma before the build-time WASM_PLACEHOLDER in apps/page/src/service-worker.ts
  • This preserves a valid ASSETS_TO_CACHE array after apps/page/build.ts injects the generated .wasm asset

• Regression coverage

  • Add a focused test in apps/page/src/service-worker-build.test.ts
  • The test replaces the placeholder the same way the build does and asserts the generated asset list keeps both entries correctly separated

• What this affects

  • Restores successful page/service worker generation for the website
  • Prevents future offline-support edits from silently breaking the generated service worker

const ASSETS_TO_CACHE = [
  `${BASE_PATH}/manifest.json`,
  // WASM_PLACEHOLDER - will be replaced at build time
];

• Screenshot
  • Restored website rendering: https://github.com/user-attachments/assets/b39280a5-120d-4e49-a2f9-89d629fa8c10

Original prompt

Last commit broke the website. Fox and validate

[Copilot]

Pull request overview

Fixes a regression in the apps/page build pipeline where apps/page/build.ts injects a WASM asset into the service worker asset cache list, and the generated service worker became syntactically invalid.

Changes:

• Add a trailing comma to the manifest.json entry in ASSETS_TO_CACHE so build-time WASM injection preserves valid array syntax.
• Add a Bun test that simulates the build-time placeholder replacement and asserts the resulting asset list remains correctly comma-separated.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
apps/page/src/service-worker.ts	Ensures ASSETS_TO_CACHE stays syntactically valid after build-time WASM asset injection.
apps/page/src/service-worker-build.test.ts	Adds regression coverage for the placeholder replacement behavior used by apps/page/build.ts.