feat(前端界面): 提示信息添加PDF

assets/webui/index.html

@@ -611,7 +611,7 @@
 			</aside>
 
 			<section class="viewer-panel" tabindex="0" aria-label="阅读区">
-				<div id="emptyState" class="empty-state">选择 OFD 文件</div>
+				<div id="emptyState" class="empty-state">选择 OFD、PDF 文件</div>
 				<div id="progressPanel" class="progress-panel" role="status" aria-live="polite" hidden>
 					<div class="progress-spinner"></div>
 					<div id="progressLabel" class="progress-label">加载中</div>

assets/webui/ofdgo.js

@@ -9,7 +9,7 @@ const PAGE_CACHE_BYTES = 32 * 1024 * 1024;
 const SCROLL_SEGMENT_SIZE = 1000000;
 const OBJECT_CLIPBOARD_TYPE = "application/x-ofdgo-objects";
 const STATUS = {
-	ready: "选择 OFD 文件",
+	ready: "选择 OFD、PDF 文件",
 	opening: "正在打开文档",
 	engine: "正在准备引擎",
 	recovering: "正在恢复引擎",
@@ -3664,7 +3664,7 @@ async function boot() {
 		}
 		if (openSeq === state.openSeq) setProgress("引擎准备完成", 70);
 		await loadExportFormats();
-		if (openSeq === state.openSeq) setEmpty("选择 OFD 文件");
+		if (openSeq === state.openSeq) setEmpty("选择 OFD、PDF 文件");
 		updateFontSummary();
 		renderFontList();
 		updateControls();
@@ -3725,6 +3725,9 @@ async function prepareOffline() {
 			location.reload();
 			return false;
 		}
+		if (navigator.storage?.persist) {
+			navigator.storage.persist().catch(() => false);
+		}
 		el.offlineStatus.textContent = "可离线";
 		watchApplicationUpdates(result.checksum);
 	} catch {
@@ -4094,7 +4097,7 @@ async function openOFD(file, remote = null) {
 	}
 	if (!remote && !isDocumentFile(file)) {
 		el.ofdInput.value = "";
-		showError(new Error("选择 OFD 文件"), !state.doc);
+		showError(new Error("选择 OFD、PDF 文件"), !state.doc);
 		return;
 	}
 	if (!discardChanges()) {