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/package.json

@@ -4,10 +4,14 @@
 	"type": "module",
 	"scripts": {
 		"dev": "wrangler dev -c wrangler.jsonc -c ../webapp/wrangler.jsonc",
-		"test": "vitest run",
-		"typecheck": "tsc -p tsconfig.check.json"
+		"types": "wrangler types",
+		"lint": "wrangler types --check && tsc -p tsconfig.json && tsc -p tests/tsconfig.json",
+		"test": "vitest run"
 	},
 	"devDependencies": {
+		"@cloudflare/vitest-plugin": "1.3.6",
+		"typescript": "^5.9.0",
+		"vitest": "4.1.11",
 		"wrangler": "^4.148.0"
 	}
 }