diigo-cache: own test toolchain; pnpm lint, pnpm test

vitest, @cloudflare/vitest-plugin, and typescript are devDependencies
here instead of being borrowed from diigo-bookmarks through hand-made
node_modules symlinks and a deep-path import.

- lint: wrangler types, then tsc over src/ and tests/ (Cloudflare's
  documented typecheck shape: regenerate types, then tsc)
- test: vitest run
- tests/tsconfig.json per the vitest-plugin docs; the dangling
  typecheck script (tsconfig.check.json never existed) is gone

Generated-by: Claude Opus 5.5

diigo-cache/README.md

@@ -85,12 +85,13 @@ const ndjson = await env.DIIGO.dumpNdjson(4, 24);
 
 ## Test
 
-    pnpm test
+    pnpm types  # regenerate worker-configuration.d.ts (after wrangler.jsonc changes)
+    pnpm lint   # fails if those types are stale; tsc over src/ and tests/
+    pnpm test   # vitest
 
-Runs the real worker and both DOs in the vitest pool, with `WEBAPP`
-bound to [a fake webapp](tests/fake-webapp.js) serving diigo-shaped
-items (`wrangler.tests.jsonc`). vitest is borrowed from
-`../diigo-bookmarks/node_modules` (see `vitest.config.ts`).
+Tests run the real worker and both DOs in the vitest pool, with
+`WEBAPP` bound to [a fake webapp](tests/fake-webapp.js) serving
+diigo-shaped items (`wrangler.tests.jsonc`).
 
 ## Run, deploy