Remove the client latest-chapter scan for lightnovelworld (#91) (#93)

Follows the spec published on #91: remove the client-side latest-chapter scan for lightnovelworld rather than porting #87's truncation into a second codebase.

- lightnovelworld.latestChapterFromAnchors deleted, not stubbed: absence is what the background-fetch guard keys off.
- computeLatestChapter tolerates an adapter with no scanner (yields null) and is exported as the test seam.
- backgroundRefreshLatest skips a scanner-less Site before the due filter: no Series page fetched, no freshness timestamp recorded, no batch slot consumed. The on-page path (maybeCaptureLatestOnSeriesPage) routes through the same null-tolerant computation.
- novelfull's scanner, the shared max-chapter helper and all four manga Sites untouched.
- userscript/AGENTS.md records the Poll-only contract for this Site and why.

All seven acceptance criteria from the spec met. node --check clean; novel suite 30/30 (the regression pin fails if a lnw scan is reintroduced, scoped or not); manga suite 35/35, manga userscript byte-for-byte unchanged.

Two-axis code review: no hard standard violations, spec-clean; one follow-up commit matching the sibling adapter guard from the manga script.

Reviewed-on: #93
Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

userscript/AGENTS.md

@@ -78,6 +78,11 @@ Guidance for OpenCode (and Claude Code) working under `userscript/`. See root `A
   the clean title on a series page and `<Title> Chapter <n>` on a chapter page.
   Its series page lists every chapter with an
   absolute href, so the backend polls it with the plain TLS client.
+  The client performs no latest-chapter scan for this Site: the Poll's
+  one-hour cooldown dominates the client's four-hour throttle, so a scan
+  would add no freshness, and the page's wpdiscuz thread is a public write
+  surface a scan would have to truncate at. `computeLatestChapter` yields
+  null here and `backgroundRefreshLatest` skips the Site before any fetch.
 
 ### Second script: `novel-bookmark.user.js`
 

userscript/novel-bookmark.user.js

@@ -218,12 +218,6 @@
       }
       return { type: "other" };
     },
-    latestChapterFromAnchors(anchors, seriesId) {
-      return maxChapter(
-        anchors,
-        new RegExp("lightnovelworld\\.net/" + escapeRe(seriesId) + "-chapter-([0-9.]+)/")
-      );
-    },
   };
 
   const ADAPTERS = [novelfull, lightnovelworld];
@@ -342,10 +336,11 @@
 
   // Highest chapter the site lists, or null when the markup yields nothing.
   // seriesId is only consulted by adapters whose pages carry other series'
-  // chapter links; the rest ignore it.
+  // chapter links. An adapter without a scanner (lightnovelworld — see the
+  // AGENTS.md entry) yields null, not an error.
   function computeLatestChapter(site, anchors, seriesId) {
     const a = adapterFor(site);
-    return a ? a.latestChapterFromAnchors(anchors, seriesId) : null;
+    return a && a.latestChapterFromAnchors ? a.latestChapterFromAnchors(anchors, seriesId) : null;
   }
 
   function currentSite() {
@@ -861,6 +856,14 @@
     const site = currentSite();
     if (!site) return;
 
+    // A Site with no client scanner (lightnovelworld) is refreshed by the Poll
+    // on a cooldown shorter than the client throttle; fetching its pages here
+    // would be a megabyte-scale request whose result is discarded. Skipping
+    // before the due filter records no freshness timestamp and consumes no
+    // per-navigation batch slot.
+    const adapter = adapterFor(site);
+    if (!adapter || !adapter.latestChapterFromAnchors) return;
+
     const checked = loadLastChecked();
     const now = Date.now();
     const due = state.list
@@ -871,7 +874,6 @@
       .slice(0, LATEST_CHECK_BATCH);
     if (due.length === 0) return;
 
-    const adapter = adapterFor(site);
     for (const bm of due) {
       // Recorded even when the fetch fails, so a broken series is retried on
       // the next throttle window rather than on every single page load.
@@ -1750,7 +1752,7 @@
   // Exposes pure logic only — see userscript/test/novel-logic.test.js.
   // ============================================================
   if (typeof window === "undefined" && typeof module === "object" && module.exports) {
-    module.exports = { novelfull, lightnovelworld, anchorsFromHTML, statusOf, kindOf, maxChapter, escapeRe, repairLnwStaleRow };
+    module.exports = { novelfull, lightnovelworld, anchorsFromHTML, statusOf, kindOf, maxChapter, escapeRe, computeLatestChapter, repairLnwStaleRow };
   }
 
   // ============================================================

userscript/test/novel-logic.test.js

@@ -45,6 +45,7 @@ globalThis.document = {
 const {
   novelfull,
   lightnovelworld,
+  computeLatestChapter,
   kindOf,
   maxChapter,
   repairLnwStaleRow,
@@ -314,17 +315,40 @@ test("lightnovelworld.detect returns other for non-series paths", () => {
   assert.equal(lightnovelworld.detect(loc("https://lightnovelworld.net/az-lists/")).type, "other");
 });
 
-test("lightnovelworld.latestChapterFromAnchors takes the max and ignores other series", () => {
-  const best = lightnovelworld.latestChapterFromAnchors(
+test("computeLatestChapter yields nothing for lightnovelworld, comment anchors included", () => {
+  // A realistic Series-page anchor set: current-slug chapters, a second
+  // Chapter Slug's chapters, and a wpdiscuz comment pasting a high-numbered
+  // chapter of another novel (the poisoning vector). The client never scans
+  // this Site — the Poll's cooldown dominates the client throttle and the
+  // comment thread is a public write surface — so this must fail the moment
+  // a scan is reintroduced, scoped or not.
+  const latest = computeLatestChapter(
+    "lightnovelworld",
     [
       { href: "https://lightnovelworld.net/a-will-eternal-chapter-1/", text: "Chapter 1" },
       { href: "https://lightnovelworld.net/a-will-eternal-chapter-1317/", text: "Chapter 1317" },
       { href: "https://lightnovelworld.net/a-will-eternal-chapter-1298/", text: "Chapter 1298" },
+      // a divergent novel's second Chapter Slug
+      { href: "https://lightnovelworld.net/my-longevity-simulation-chapter-400/", text: "Chapter 400" },
+      // a wpdiscuz comment anchor
       { href: "https://lightnovelworld.net/overgeared-chapter-9999/", text: "Chapter 9999" },
     ],
     "a-will-eternal"
   );
-  assert.deepEqual(best, { num: 1317, label: "Chapter 1317" });
+  assert.equal(latest, null);
+});
+
+test("computeLatestChapter still scans novelfull and ignores other series", () => {
+  const best = computeLatestChapter(
+    "novelfull",
+    [
+      { href: "/reverend-insanity/chapter-2334-fang-yuan.html", text: "Chapter 2334" },
+      { href: "/reverend-insanity/chapter-1.html", text: "Chapter 1" },
+      { href: "/release-that-witch/chapter-9999.html", text: "Chapter 9999" },
+    ],
+    "reverend-insanity"
+  );
+  assert.deepEqual(best, { num: 2334, label: "Chapter 2334" });
 });
 
 test("latestChapterFromAnchors returns null when nothing matches", () => {