feat(reader): in-book search for reflowable formats

Wires foliate's search engine into the new drawer system:

- 🔍 topbar button (reflowable-only; PDF/comic sections have no
  searchable text documents) and the '/' keyboard shortcut open a
  Search drawer: query input (Enter to run), live progress while
  scanning (per-section percent), match count, and results grouped
  by section with TOC labels.
- Each result shows pre/match/post excerpt rendered as three text
  nodes (no x-html — book content never enters the DOM as markup);
  the match is styled with a translucent <mark>. Clicking jumps to
  the hit's CFI and closes the drawer.
- Hits are drawn on the page through foliate's overlayer (outline
  style) and persist across page turns — the engine re-applies
  search results when a section's overlay is created. Clearing the
  query removes the outlines.
- A generation counter discards results and progress from superseded
  searches (rapid re-query), and starting a new search clears the
  previous one server-side via view.clearSearch().
- Search integrates with the drawer system: scrim, Esc-to-close,
  one-drawer-at-a-time, / focuses the input via .

web/src/reader/reader.ts

@@ -401,6 +401,15 @@ document.addEventListener("alpine:init", () => {
     annotationsTab: "highlights" as string,
     newNoteText: "",
     highlightColors: HIGHLIGHT_COLORS,
+    searchOpen: false,
+    searchQuery: "",
+    searchGroups: [] as {
+      label: string;
+      items: { cfi: string; pre: string; match: string; post: string }[];
+    }[],
+    searchProgress: 0,
+    searching: false,
+    searchGen: 0,
     selectionPopover: {
       open: false,
       mode: "create" as "create" | "edit",
@@ -477,6 +486,12 @@ document.addEventListener("alpine:init", () => {
         };
       });
     },
+    get searchMatchCount(): number {
+      return this.searchGroups.reduce(
+        (n: number, g: { items: unknown[] }) => n + g.items.length,
+        0,
+      );
+    },
     init() {
       const link = document.getElementById("reader-back");
       if (!link) return;
@@ -1425,13 +1440,80 @@ document.addEventListener("alpine:init", () => {
       this.closeDrawers();
       this.bookmarksOpen = opening;
     },
+    toggleSearch() {
+      if (this.isFixedLayout) return; // search requires reflowable text
+      const opening = !this.searchOpen;
+      this.closeDrawers();
+      this.searchOpen = opening;
+      if (opening) {
+        (this as any).$nextTick(() =>
+          (this as any).$refs.searchInput?.focus(),
+        );
+      }
+    },
     anyDrawerOpen(): boolean {
-      return this.tocOpen || this.settingsOpen || this.bookmarksOpen;
+      return this.tocOpen || this.settingsOpen || this.bookmarksOpen || this.searchOpen;
     },
     closeDrawers() {
       this.tocOpen = false;
       this.settingsOpen = false;
       this.bookmarksOpen = false;
+      this.searchOpen = false;
+    },
+    // ----- in-book search (reflowable) -----
+    // view.search() is an async generator: it progressively scans sections,
+    // yields {progress} per section and {label, subitems} per section with
+    // hits, and draws outline highlights through the overlayer pipeline.
+    // A generation counter discards results from superseded searches.
+    async runSearch() {
+      const q = this.searchQuery.trim();
+      if (!q) {
+        this.clearSearchResults();
+        return;
+      }
+      this.searchGen++;
+      const gen = this.searchGen;
+      this.searching = true;
+      this.searchProgress = 0;
+      this.searchGroups = [];
+      try {
+        for await (const r of this.view.search({ query: q })) {
+          if (gen !== this.searchGen) return;
+          if (r === "done") break;
+          if (r && typeof r === "object") {
+            if (typeof r.progress === "number") {
+              this.searchProgress = r.progress;
+              continue;
+            }
+            if (Array.isArray(r.subitems) && r.subitems.length) {
+              this.searchGroups.push({
+                label: r.label || `Section ${this.searchGroups.length + 1}`,
+                items: r.subitems.map((s: any) => ({
+                  cfi: s.cfi,
+                  pre: s.excerpt?.pre ?? "",
+                  match: s.excerpt?.match ?? "",
+                  post: s.excerpt?.post ?? "",
+                })),
+              });
+            }
+          }
+        }
+      } catch (_e) {
+        /* search errors leave partial results */
+      }
+      if (gen === this.searchGen) this.searching = false;
+    },
+    clearSearchResults() {
+      this.searchGen++;
+      this.searching = false;
+      this.searchGroups = [];
+      this.searchProgress = 0;
+      this.view?.clearSearch?.();
+    },
+    goToSearchResult(cfi: string) {
+      if (!cfi) return;
+      this.view?.goTo?.(cfi);
+      this.closeDrawers();
     },
     flattenTOC(items: any[], depth = 0): any[] {
       const result: any[] = [];
@@ -1923,6 +2005,10 @@ document.addEventListener("alpine:init", () => {
         if (k === "t") this.toggleTOC();
         else if (k === "s") this.toggleSettings();
         else if (k === "b") this.addBookmark();
+        else if (k === "/") {
+          event.preventDefault();
+          this.toggleSearch();
+        }
       }
     },
   }));