fix(web): banner highlight delete; retention wording states the days

The book-detail banner's highlight rows gain Delete (tombstoned
server-side, restorable from the Deleted modal — same as the reader
drawers already offered). The deleted-annotations modal now says the
retention in plain language — 'kept for 30 days' from the
annotation_tombstone_ttl_days tunable (threaded through BookDetail →
NotesHighlightsModal; 1-day singular and retention-disabled variants
handled) — instead of referencing a settings name a reader cannot see.

internal/router/frontend.go

@@ -1436,7 +1436,10 @@ func registerFrontendRoutes(cfg *Config) {
 
 		// Render template
 		var buf bytes.Buffer
-		err = templates.BookDetail(user, detail, "").Render(c.Request().Context(), &buf)
+		// The deleted-annotations modal states the retention in plain days
+		// (the tunable's user-facing value), never as a settings name.
+		tombstoneDays := cfg.Settings.TombstoneTTL() / (24 * time.Hour)
+		err = templates.BookDetail(user, detail, "", int(tombstoneDays)).Render(c.Request().Context(), &buf)
 		if err != nil {
 			return err
 		}

templates/annotations_banner.templ

@@ -99,8 +99,7 @@ templ AnnotationsBanner(book handlers.MediaDetail) {
 								></button>
 								<button
 									type="button"
-									x-show="row.kind === 'note'"
-									@click="deleteBannerNote(row)"
+									@click="row.kind === 'note' ? deleteBannerNote(row) : deleteBannerHighlight(row)"
 									class="text-xs px-2 py-1 rounded-lg hover:bg-surface-hover"
 									style="color: var(--status-danger);"
 								>✕ Delete</button>

templates/book_detail.templ

@@ -9,7 +9,7 @@ import (
 	"strings"
 )
 
-templ BookDetail(user User, book handlers.MediaDetail, errorMessage string) {
+templ BookDetail(user User, book handlers.MediaDetail, errorMessage string, tombstoneDays int) {
 	<!DOCTYPE html>
 	<html lang="en">
 		<head>
@@ -440,7 +440,7 @@ templ BookDetail(user User, book handlers.MediaDetail, errorMessage string) {
 				}
 			</div>
 			@ProgressSyncModal(user, book)
-			@NotesHighlightsModal(user, book)
+			@NotesHighlightsModal(user, book, tombstoneDays)
 			@AnnotationsBanner(book)
 			if user.Role == "admin" {
 				@MetadataEditorModal(book)

templates/book_detail_modals.templ

@@ -128,7 +128,7 @@ templ ProgressSyncModal(user User, book handlers.MediaDetail) {
 	</div>
 }
 
-templ NotesHighlightsModal(user User, book handlers.MediaDetail) {
+templ NotesHighlightsModal(user User, book handlers.MediaDetail, tombstoneDays int) {
 	<div
 		id="notes-modal"
 		class="hidden fixed inset-0 z-50 flex items-center justify-center overflow-y-auto p-4"
@@ -183,7 +183,13 @@ templ NotesHighlightsModal(user User, book handlers.MediaDetail) {
 						<span class="badge" style="background-color: var(--accent-muted); color: var(--accent);">{ len(book.DeletedAnnotations) }</span>
 					</div>
 					<p class="text-xs mb-4" style="color: var(--text-secondary);">
-						Deleted entries are kept for the sync retention window before being removed automatically. Restore returns them to every synced device; Delete permanently removes them immediately.
+						if tombstoneDays == 1 {
+							Deleted entries are kept for 1 day before being removed automatically. Restore returns them to every synced device; Delete permanently removes them immediately.
+						} else if tombstoneDays > 1 {
+							Deleted entries are kept for { tombstoneDays } days before being removed automatically. Restore returns them to every synced device; Delete permanently removes them immediately.
+						} else {
+							Deleted entries are kept until manually purged (retention disabled). Restore returns them to every synced device; Delete permanently removes them immediately.
+						}
 					</p>
 					<div class="space-y-3">
 						for _, ann := range book.DeletedAnnotations {

templates/book_detail_templ.go

@@ -17,7 +17,7 @@ import (
 	"strings"
 )
 
-func BookDetail(user User, book handlers.MediaDetail, errorMessage string) templ.Component {
+func BookDetail(user User, book handlers.MediaDetail, errorMessage string, tombstoneDays int) templ.Component {
 	return templruntime.GeneratedTemplate(func(templ_7745c5c3_Input templruntime.GeneratedComponentInput) (templ_7745c5c3_Err error) {
 		templ_7745c5c3_W, ctx := templ_7745c5c3_Input.Writer, templ_7745c5c3_Input.Context
 		if templ_7745c5c3_CtxErr := ctx.Err(); templ_7745c5c3_CtxErr != nil {
@@ -1396,7 +1396,7 @@ func BookDetail(user User, book handlers.MediaDetail, errorMessage string) templ
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = NotesHighlightsModal(user, book).Render(ctx, templ_7745c5c3_Buffer)
+		templ_7745c5c3_Err = NotesHighlightsModal(user, book, tombstoneDays).Render(ctx, templ_7745c5c3_Buffer)
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}

web/src/book-detail.ts

@@ -311,6 +311,23 @@ Alpine.data("bookDetail", () => {
         showToast("Could not delete the note", "error");
       }
     },
+    async deleteBannerHighlight(row: AnnotationRow) {
+      if (row.kind !== "highlight") return;
+      const mediaId = getMediaId();
+      const hlId = row.key.slice("hl-".length);
+      try {
+        const resp = await fetch(`/api/media-items/${mediaId}/highlights/${hlId}`, {
+          method: "DELETE",
+          headers: { Authorization: getAuthHeader() },
+        });
+        if (!resp.ok) throw new Error(String(resp.status));
+        // Tombstoned server-side: restorable from the Deleted modal.
+        showToast("Highlight deleted — restorable from Deleted", "success");
+        await this.fetchBannerAnnotations();
+      } catch (_e) {
+        showToast("Could not delete the highlight", "error");
+      }
+    },
     showExportDialog(): void {
       if (this.bannerRows.length === 0) return;
       this.annotationsExportOpen = true;