feat(ui): add Rescan button to Edit Metadata dialog

Adds a Rescan button to the MetadataEditorModal footer that POSTs to the
new per-book rescan endpoint, with rescanning state (disabled + spinner,
matching the existing Mark Read pattern), success/error toasts, and a
page reload to pick up the refreshed cover and metadata.

templates/book_detail_modals.templ

@@ -609,7 +609,19 @@ templ MetadataEditorModal(book handlers.MediaDetail) {
 					</div>
 				</div>
 			</div>
-			<div class="flex justify-end space-x-3 p-6 border-t flex-shrink-0" style="border-color: var(--border);">
+		<div class="flex items-center justify-between p-6 border-t flex-shrink-0" style="border-color: var(--border);">
+			<button
+				@click="rescanBook()"
+				:disabled="rescanning"
+				class="btn btn-secondary"
+			>
+				<span x-show="!rescanning" class="inline-flex items-center gap-2">@Icon("sync", "h-4 w-4")<span>Rescan</span></span>
+				<svg x-show="rescanning" class="animate-spin inline-block h-5 w-5" viewBox="0 0 24 24" fill="none">
+					<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
+					<path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z"></path>
+				</svg>
+			</button>
+			<div class="flex space-x-3">
 				<button
 					@click="hideMetadataEditor()"
 					class="btn btn-secondary"
@@ -625,5 +637,6 @@ templ MetadataEditorModal(book handlers.MediaDetail) {
 				</button>
 			</div>
 		</div>
+		</div>
 	</div>
 }

templates/book_detail_modals_templ.go

@@ -1336,7 +1336,15 @@ func MetadataEditorModal(book handlers.MediaDetail) templ.Component {
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 126, "\" readonly class=\"input opacity-60\"></div></div></div></div></div></div><div class=\"flex justify-end space-x-3 p-6 border-t flex-shrink-0\" style=\"border-color: var(--border);\"><button @click=\"hideMetadataEditor()\" class=\"btn btn-secondary\">Cancel</button> <button @click=\"saveMetadata()\" class=\"btn btn-primary\">")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 126, "\" readonly class=\"input opacity-60\"></div></div></div></div></div></div><div class=\"flex items-center justify-between p-6 border-t flex-shrink-0\" style=\"border-color: var(--border);\"><button @click=\"rescanBook()\" :disabled=\"rescanning\" class=\"btn btn-secondary\"><span x-show=\"!rescanning\" class=\"inline-flex items-center gap-2\">")
+		if templ_7745c5c3_Err != nil {
+			return templ_7745c5c3_Err
+		}
+		templ_7745c5c3_Err = Icon("sync", "h-4 w-4").Render(ctx, templ_7745c5c3_Buffer)
+		if templ_7745c5c3_Err != nil {
+			return templ_7745c5c3_Err
+		}
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 127, "<span>Rescan</span></span> <svg x-show=\"rescanning\" class=\"animate-spin inline-block h-5 w-5\" viewBox=\"0 0 24 24\" fill=\"none\"><circle class=\"opacity-25\" cx=\"12\" cy=\"12\" r=\"10\" stroke=\"currentColor\" stroke-width=\"4\"></circle> <path class=\"opacity-75\" fill=\"currentColor\" d=\"M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z\"></path></svg></button><div class=\"flex space-x-3\"><button @click=\"hideMetadataEditor()\" class=\"btn btn-secondary\">Cancel</button> <button @click=\"saveMetadata()\" class=\"btn btn-primary\">")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
@@ -1344,7 +1352,7 @@ func MetadataEditorModal(book handlers.MediaDetail) templ.Component {
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 127, "Save</button></div></div></div>")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 128, "Save</button></div></div></div></div>")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}

web/src/book-detail.ts

@@ -97,6 +97,7 @@ interface MetadataEditorState {
   coverFile: Blob | null;
   coverAction: string;
   saving: boolean;
+  rescanning: boolean;
   userRating: number;
   ratingHover: number;
   ratingSaving: boolean;
@@ -110,6 +111,7 @@ interface MetadataEditorState {
   generateCover(): Promise<void>;
   removeCover(): void;
   saveMetadata(): Promise<void>;
+  rescanBook(): Promise<void>;
   starFill(i: number): string;
   ratingText(): string;
   setRating(value: number): Promise<void>;
@@ -149,6 +151,7 @@ Alpine.data("bookDetail", () => {
     coverFile: null as Blob | null,
     coverAction: "keep",
     saving: false,
+    rescanning: false,
     userRating: 0,
     ratingHover: 0,
     ratingSaving: false,
@@ -559,6 +562,31 @@ Alpine.data("bookDetail", () => {
       }
     },
 
+    async rescanBook() {
+      if (this.rescanning) return;
+      this.rescanning = true;
+      const mediaId = getMediaId();
+      try {
+        const resp = await fetch(`/api/media-items/${mediaId}/rescan`, {
+          method: "POST",
+          headers: { Authorization: getAuthHeader() },
+        });
+        if (!resp.ok) {
+          const err = await resp.json().catch(() => ({}));
+          throw new Error(err.error || "Failed to rescan book");
+        }
+        showToast("Book rescanned successfully", "success");
+        setTimeout(() => window.location.reload(), 500);
+      } catch (e) {
+        showToast(
+          e instanceof Error ? e.message : "Failed to rescan book",
+          "error",
+        );
+      } finally {
+        this.rescanning = false;
+      }
+    },
+
     async searchEditorTags() {
       const libraryId = document.body.getAttribute("data-library-id") || "";
       if (!this.tagSearch || this.tagSearch.length < 2 || !libraryId) {