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/tsconfig.json

@@ -7,6 +7,7 @@
 		"esModuleInterop": true,
 		"verbatimModuleSyntax": true,
 		"skipLibCheck": true,
+		"lib": ["ES2022", "ESNext.Disposable"],
 		"noEmit": true,
 		"types": []
 	},