diigo-cache: bookmark cache in Durable Objects (goal 1c)

The dump worker becomes a page cache: a hit is served from DO SQLite
storage with no diigo call; a miss asks the webapp instance in the
cache's wiring and etches the page.

- two independent caches, one behavior (PagedCache): DiigoCache keeps
  every item; PublicCache keeps shared items only, dropping private
  rows before they are stored; served at /public/<username> (HTML page
  form, or JSON)
- create flow on one port: /_connect relays webapp's mint form, /_mint
  proxies the mint, /_wire wires a private or public cache; /_publish
  adds a public cache later
- ids are webkeys: kept out of URLs (POST bodies), shown and logged
  only as a hash fingerprint; saved to the password manager under the
  holder's petname (never sent to the server)
- items keyed on diigo's link_id; username from u_name; unkeyable
  items and every failure path are logged; each page read logs hit/miss
- tests run the real worker + DOs in the vitest pool against a fake
  webapp (tests/fake-webapp.js)

Generated-by: opencode (GLM)
Generated-by: Claude Opus 5.5

diigo-cache/vitest.config.ts

@@ -0,0 +1,28 @@
+import { defineProject } from "vitest/config";
+// the plugin resolves from diigo-bookmarks's store (the one vitest
+// install on disk); direct-path import sidesteps pnpm's exports-map
+// restriction *for the config file*. cloudflareTest (the plugin form,
+// not the bare pool) is what provides the `cloudflare:test` module.
+import { cloudflareTest } from "../diigo-bookmarks/node_modules/.pnpm/@cloudflare+vitest-plugin@1.3.6_@cloudflare+workers-types@5.20261005.1_@types+node@26.6.4_@vi_7mty7nznaeeyt2ohspxbzj4p6m/node_modules/@cloudflare/vitest-plugin/dist/pool/index.mjs";
+
+export default defineProject({
+	plugins: [
+		cloudflareTest({
+			// the real worker + DOs; WEBAPP is a fake (aux workers must be JS)
+			wrangler: { configPath: "./wrangler.tests.jsonc" },
+			miniflare: {
+				workers: [
+					{
+						name: "fake-webapp",
+						modules: true,
+						scriptPath: "./tests/fake-webapp.js",
+						compatibilityDate: "2026-09-29",
+					},
+				],
+			},
+		}),
+	],
+	test: {
+		include: ["tests/**/*.test.ts"],
+	},
+});