fix: truncate article titles to safe UTF-8 budget

browser/importer.js

@@ -153,12 +153,31 @@
         return output.join('\n').trim();
     }
 
+    function shortTitle(title, budget = 75) {
+        const size = ch => {
+            const code = ch.codePointAt(0);
+            return code <= 0x7f ? 1 : code <= 0x7ff ? 2 : code <= 0xffff ? 3 : 4;
+        };
+        // A generated prefix plus "..." (up to 78 bytes) is already safe.
+        const total = Array.from(title).reduce((sum, ch) => sum + size(ch), 0);
+        if (total <= budget || (title.endsWith('...') && total <= budget + 3)) return title;
+        let prefix = '', used = 0;
+        for (const ch of title) {
+            const bytes = size(ch);
+            if (used + bytes > budget) break;
+            prefix += ch;
+            used += bytes;
+        }
+        return prefix + '...';
+    }
+
     function compile(markdown, mdPath, fileMap, titleOverride) {
         let body = String(markdown).replace(/^\uFEFF/, '').replace(/\r\n?/g, '\n');
         const firstHeading = body.match(/^\s*#\s+([^\n]+)\n?/);
-        const title = String(titleOverride || firstHeading?.[1] || mdPath.split('/').pop().replace(/\.md$/i, '')).trim();
+        const originalTitle = String(titleOverride || firstHeading?.[1] || mdPath.split('/').pop().replace(/\.md$/i, '')).trim();
+        const title = shortTitle(originalTitle);
         if (firstHeading) body = body.slice(firstHeading[0].length).trim();
-        if (!title || Array.from(title).length > 80) throw new Error('标题为空或超过 80 字，请修改 Markdown 标题后重试。');
+        if (!title) throw new Error('标题为空，请修改 Markdown 标题后重试。');
         if (!body.trim()) throw new Error('正文为空。');
         const warnings = [];
         if (/<\/?[a-z][^>]*>/i.test(body)) warnings.push('存在 HTML，将作为文字保留；请检查排版。');
@@ -531,5 +550,5 @@
         $('diagnostics').onclick = () => downloadJSON({ ...summary(), logs }, 'dww11-import-diagnostics.json');
         win.addEventListener('pagehide', releasePreviews, { once: true });
     }
-    return { VERSION, normalizePath, imagePath, readLink, markdownToBBCode, compile, prepareFiles, preparePackage, parseAid, attachmentId, verifyEditorImages, mount };
+    return { VERSION, shortTitle, normalizePath, imagePath, readLink, markdownToBBCode, compile, prepareFiles, preparePackage, parseAid, attachmentId, verifyEditorImages, mount };
 });