diigo-cache: dispose RPC stubs after each fetch; one fetch per miss

Two bugs in page()'s miss path, found while building the fill job:

- the webapp stubs (app, pathjoin, query) were never disposed, which
  kept the DO from being evicted (evictDurableObject hung after a single
  miss); they are now disposed once the page is in hand
- a miss on page n > 1 also fetched page 1 and threw it away, doubling
  diigo calls; every page carries `total`, so only page n is fetched

Regression test: a miss, then eviction, then a cache hit. tsconfig adds
the ESNext.Disposable lib for Symbol.dispose.

Generated-by: Claude Opus 5.5

diigo-cache/tests/caches.test.ts

@@ -1,5 +1,5 @@
 import { env } from "cloudflare:workers";
-import { runInDurableObject } from "cloudflare:test";
+import { evictDurableObject, runInDurableObject } from "cloudflare:test";
 import { describe, expect, it, vi } from "vitest";
 import worker from "../src/index.js";
 import { toWebkey } from "../src/webkeys.js";
@@ -68,6 +68,16 @@ describe("PublicCache", () => {
 	});
 });
 
+describe("eviction", () => {
+	it("a cache miss leaves no undisposed RPC stubs to block eviction", async () => {
+		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());
+		await stub.setup({ webappId: WEBAPP_ID });
+		await stub.page(1, 24);
+		await evictDurableObject(stub);
+		expect((await stub.page(1, 24)).cached).toBe(true);
+	}, 3000);
+});
+
 describe("DiigoCache", () => {
 	it("keeps every item of a page, each under its own link_id", async () => {
 		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());