[kazupon]

Closes #62

The Service Worker now serves public files (/public/…) that are passed to ready() or added with the file methods.

Cause

The Service Worker's dev server read the public directory once, when it started. At that point its virtual filesystem held only /public/.gitkeep, because the project files arrive later through V_FS_* messages. The list was never updated afterwards, so servePublicMiddleware skipped every public file, and the request got the SPA fallback index.html.

Fix

• The new syncPublicFiles() (public-files-sync.ts) updates the list on the watcher's add and unlink events. Vite does the same in the watcher handlers of _createServer(), and the Web Worker already did it in setupHMR().
• The list is updated synchronously in the event. The Service Worker acknowledges a file change after applying it (feat(vrowzer): resolve file operations after the Workers apply them #61). So when addFile(), updateFile() or deleteFile() resolves, the change is visible for public files too.
• Two differences from Vite:
  • The public directory is checked with a trailing slash, so that a sibling such as /publicity.js is not taken for a public file.
  • Vite also removes the etag of a module with the same path. The Service Worker has no module graph, so that part is not needed.
• The README and the JSDoc of addFile() no longer describe this as a limitation.

Behavior change

A public file now wins over a module with the same path, as in Vite. If both /public/x.js and /x.js exist, a request for /x.js gets the public file, without any transform. Before, public files were never served, so the module was returned.

Not included

• Files that arrive while the Service Worker starts: an add event that comes after the initial read of the directory, but before the watcher listener is attached, would be missed.
  • This does not happen in the normal flow: ready() waits until the Service Worker's dev server has started before it sends any file.
  • It can happen right after a Service Worker restart, which Recover project files and channels after Service Worker process restart #46 covers.
• Binary files given to ready(): both Workers write them as the string [object ArrayBuffer], because they are sent and written as text.
  • This also affects public images given to ready(), which are now served with that content.
  • Binary files added later with addFile() are not affected.
  • This will be tracked separately.
• Debug logging: every Service Worker middleware still logs each request with console.log. This will be cleaned up separately.

Tests

• Unit tests:

  • public-files-sync.test.ts covers:

    • adding and deleting files under the public directory, including nested directories;
    • files outside it, including /publicity.js and /public/../secret.txt;
    • change events and path normalization;
    • that the list is already updated when notify() returns.

    These tests failed before the change, because the function did not exist.

  • static.test.ts: the middleware follows changes to the list after it has been created. This test passed before the change. It records that the middleware itself needs no change.

• Integration tests in the shared playground, which read through the Service Worker from the host page:

  • a public file given to ready() is served with its content and Content-Type;
  • public files added, updated and deleted with the file methods are served, or no longer served, right after the promises resolve, without polling;
  • binary public files keep their bytes;
  • a public file is served instead of a module with the same path.

  All four tests fail when the Service Worker does not call syncPublicFiles().

Validated locally with:

• vp run test:unit: 119 files, 1,907 tests
• vp run test:integration:vrowzer: 64 passed and 1 conditional skip, in two consecutive runs and once more after the docs change
• vp run test:e2e: 46 passed, 6 existing test.skip
• oxlint (no new warnings), knip, the format check of the changed files, and typecheck