diigo-cache: invalidate the last N days of cached pages

invalidateRecent(days) drops the cached pages holding anything diigo
updated within the last N days (on the cache's injected clock), and
every page before them, so the next read or fill refetches them; item
rows stay. Exposed on the fill capability (private and public) and on
the webkey page as "invalidate the last N days" per cache.

A user-requested refetch, not a change in what stored state means.

Generated-by: Claude Opus 5.5

diigo-cache/src/cache-page.ts

@@ -28,12 +28,18 @@ export const CACHE_PAGE_HTML = `<!doctype html>
 <p id="private-status">no fill job yet</p>
 <button type="button" data-target="private" data-action="start">fill</button>
 <button type="button" data-target="private" data-action="stop">stop</button>
+<p><label>invalidate the last <input type="number" id="private-days" min="1" max="3650" value="7" size="5"> days</label>
+<button type="button" data-target="private" data-action="invalidate">invalidate</button>
+<span id="private-invalidated"></span></p>
 </section>
 <section id="public" hidden>
 <h2>public cache</h2>
 <p id="public-status">no fill job yet</p>
 <button type="button" data-target="public" data-action="start">fill</button>
 <button type="button" data-target="public" data-action="stop">stop</button>
+<p><label>invalidate the last <input type="number" id="public-days" min="1" max="3650" value="7" size="5"> days</label>
+<button type="button" data-target="public" data-action="invalidate">invalidate</button>
+<span id="public-invalidated"></span></p>
 </section>
 <p><a href="/">← home</a></p>
 <script type="module">
@@ -105,6 +111,13 @@ async function main() {
 		button.addEventListener("click", () => {
 			const { target, action } = button.dataset;
 			const j = job(target);
+			if (action === "invalidate") {
+				const days = Number($(target + "-days").value);
+				j.invalidateRecent(days)
+					.then((r) => ($(target + "-invalidated").textContent = "dropped " + r.pages + " cached pages; fill to refetch"))
+					.catch(report);
+				return;
+			}
 			(action === "start" ? j.startFill() : j.stopFill())
 				.then(() => refresh(hasPublic))
 				.catch(report);