fix(userscript): read comix titles from document.title, parse kagane volume chapters

comix.to is an SPA whose client router rewrites document.title but never
touches the server-rendered og:title. The adapter read og:title, so a
bookmark taken after a cold load got the homepage's title ("Comix - Read
Comics online for free") and one taken after an in-page hop got the
previous series' title. Titles now come from document.title, with the
chapter page's " - Ch.<n>" tail stripped.

comix also serves no og:image at all, which is why every comix bookmark
fell back to the monogram placeholder. The cover is now the img whose alt
matches the cleaned title.

Both fixes need the page to have finished its client-side route change,
and comix fills document.title a beat after the URL changes - later than
the nav watcher's 300ms snapshot. The watcher therefore also re-detects
when the detect() signature changes, not only when the URL does.

kagane reader URLs carry no chapter number, so it comes out of og:title.
Volume-numbered series render "<Series> - Volume <v> Chapter <n>" with no
episode name, a shape the suffix regex did not match. One unmatched title
caused both reported symptoms: the volume tail stayed in the stored title
("SP Baby - Volume 1 Chapter 1"), and chapterNum came back null so no
chapter was ever recorded for the series. The regex now takes an optional
"Volume <v> " segment.

All three page shapes were captured live on 2026-08-08 and are pinned as
regression tests in userscript/test/logic.test.js.

userscript/test/logic.test.js

@@ -31,6 +31,9 @@ globalThis.location = {
 
 // og: meta tags the adapters read through meta(). Reassigned per test.
 let metaTags = {};
+// document.title. comix's SPA rewrites this on client routing but never
+// og:title, so the comix adapter reads it instead. Reassigned per test.
+let docTitle = "";
 // img[alt] elements comix's coverFromPage() scans. Reassigned per test; each
 // entry is {alt, src}.
 let pageImages = [];
@@ -48,6 +51,9 @@ globalThis.document = {
     }));
   },
   addEventListener() {},
+  get title() {
+    return docTitle;
+  },
   body: undefined,
 };
 
@@ -193,8 +199,15 @@ test("comixSeriesId leaves a bare id untouched", () => {
   assert.equal(comixSeriesId("n8we"), "n8we");
 });
 
+// comix is an SPA that rewrites document.title on client routing but leaves the
+// server-rendered og:title untouched, so every test here pins og:title to a
+// STALE value — the homepage title on first hop, the previous series after
+// that. Captured live 2026-08-08.
+const COMIX_STALE_HOME = "Comix - Read Comics online for free";
+
 test("comix detects a series page", () => {
-  metaTags = { "og:title": "Dungeons and Crayons" };
+  metaTags = { "og:title": COMIX_STALE_HOME };
+  docTitle = "Dungeons and Crayons";
   const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
   assert.equal(p.type, "series");
   assert.equal(p.site, "comix");
@@ -204,8 +217,16 @@ test("comix detects a series page", () => {
   assert.equal(p.chapterNum, null);
 });
 
+test("comix ignores a previous series' stale og:title", () => {
+  metaTags = { "og:title": "Full-Time Awakening" };
+  docTitle = "Dungeons and Crayons";
+  const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
+  assert.equal(p.title, "Dungeons and Crayons");
+});
+
 test("comix detects a chapter page and strips the Ch. suffix from the title", () => {
-  metaTags = { "og:title": "Dungeons and Crayons · Ch.80" };
+  metaTags = { "og:title": COMIX_STALE_HOME };
+  docTitle = "Dungeons and Crayons · Ch.80";
   const p = comix.detect(
     loc("https://comix.to/title/n8we-dungeons-and-crayons/11139891-chapter-80")
   );
@@ -218,7 +239,8 @@ test("comix detects a chapter page and strips the Ch. suffix from the title", ()
 });
 
 test("comix parses decimal chapter numbers", () => {
-  metaTags = { "og:title": "Dungeons and Crayons · Ch.80.5" };
+  metaTags = {};
+  docTitle = "Dungeons and Crayons · Ch.80.5";
   const p = comix.detect(
     loc("https://comix.to/title/n8we-dungeons-and-crayons/11139891-chapter-80.5")
   );
@@ -226,19 +248,19 @@ test("comix parses decimal chapter numbers", () => {
 });
 
 test("comix.detect reads the cover from an img whose alt matches the cleaned title", () => {
-  metaTags = { "og:title": "Dungeons and Crayons · Ch.80" };
+  metaTags = { "og:title": COMIX_STALE_HOME };
+  docTitle = "Dungeons and Crayons";
   pageImages = [
     { alt: "Some Other Series", src: "https://cdn.example/other.jpg" },
     { alt: "Dungeons and Crayons", src: "https://cdn.example/cover.jpg" },
   ];
-  const p = comix.detect(
-    loc("https://comix.to/title/n8we-dungeons-and-crayons/11139891-chapter-80")
-  );
+  const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
   assert.equal(p.cover, "https://cdn.example/cover.jpg");
 });
 
 test("comix.detect leaves cover empty when no img alt matches the title", () => {
-  metaTags = { "og:title": "Dungeons and Crayons" };
+  metaTags = {};
+  docTitle = "Dungeons and Crayons";
   pageImages = [{ alt: "Some Other Series", src: "https://cdn.example/other.jpg" }];
   const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
   assert.equal(p.cover, "");
@@ -315,6 +337,33 @@ test("kagane reads the chapter number out of og:title", () => {
   assert.equal(p.seriesUrl, "https://kagane.to/series/" + KAGANE_SERIES);
 });
 
+// Volume-numbered series render the suffix as "- Volume <v> Chapter <n>" with
+// no episode name, because the book carries volume_no and an empty title.
+// Captured live 2026-08-08 from SP Baby.
+test("kagane reads through a Volume-numbered chapter suffix", () => {
+  metaTags = {
+    "og:title": "SP Baby - Volume 1 Chapter 1",
+    "og:image": "https://kagane.to/api/v2/image/abc/compressed",
+  };
+  const p = kagane.detect(
+    loc("https://kagane.to/series/" + KAGANE_SERIES + "/reader/" + KAGANE_BOOK)
+  );
+  assert.equal(p.title, "SP Baby");
+  assert.equal(p.chapterNum, 1);
+  assert.equal(p.chapterLabel, "Chapter 1");
+});
+
+// A book with neither a volume nor an episode name ends the title right after
+// the number, which the old trailing-\s regex could not match.
+test("kagane reads a chapter suffix with no episode name", () => {
+  metaTags = { "og:title": "Some Series - Chapter 7.5" };
+  const p = kagane.detect(
+    loc("https://kagane.to/series/" + KAGANE_SERIES + "/reader/" + KAGANE_BOOK)
+  );
+  assert.equal(p.title, "Some Series");
+  assert.equal(p.chapterNum, 7.5);
+});
+
 test("kagane yields a null chapterNum when og:title has no chapter", () => {
   metaTags = { "og:title": "Infinite Decryption: The Strongest Level 0" };
   const p = kagane.detect(