Refactor code editor out of main UI + PubMed FTP PDF + login token fix

- Move code editor to standalone page; remove from main index/app mode switcher
- Add diff-active tab highlight and diff bar CSS to styles
- Add markdown table styles for chat messages
- PubMed: try NCBI FTP link before Unpaywall for PDF download
- Login: also persist token to localStorage for cross-tab auth
- Update skills state and config

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/tools/pubmed.ts

@@ -317,6 +317,13 @@ export const pubmedFulltextTool = {
       }
 
       if (args?.format === 'pdf') {
+        // Extract FTP PDF link directly from OA API XML (most reliable source)
+        let ftpPdfUrl = '';
+        const ftpMatch = oaXml.match(/href="(ftp:\/\/[^"]+\.pdf)"/i);
+        if (ftpMatch) {
+          ftpPdfUrl = ftpMatch[1].replace('ftp://ftp.ncbi.nlm.nih.gov/', 'https://ftp.ncbi.nlm.nih.gov/');
+        }
+
         // PDF mode: get DOI via single PMC esummary call, then Unpaywall
         const apiKey = getPubMedApiKey();
         const sumParams = new URLSearchParams({ db: 'pmc', id: numericId, retmode: 'json' });
@@ -336,19 +343,7 @@ export const pubmedFulltextTool = {
           } catch {}
         }
 
-        if (!pdfUrl) {
-          return {
-            success: false,
-            error: [
-              `No downloadable PDF found for ${pmcid}${doi ? ` (DOI: ${doi})` : ''}.`,
-              `The article is OA but the PDF is not accessible via Unpaywall.`,
-              `Try format "text" to get the plain-text version instead.`,
-              doi ? `Publisher page: https://doi.org/${doi}` : '',
-            ].filter(Boolean).join('\n'),
-          };
-        }
-
-        // Download PDF — try Unpaywall URL first, then Europe PMC as fallback
+        // Download PDF — try NCBI FTP first, then Unpaywall, then Europe PMC
         const workspaceDir = getWorkspacePath(args);
         const pdfDir = path.join(workspaceDir, 'pubmed');
         fs.mkdirSync(pdfDir, { recursive: true });
@@ -358,7 +353,7 @@ export const pubmedFulltextTool = {
           : path.join(pdfDir, `${pmcid}.pdf`);
 
         const europePmcUrl = `https://europepmc.org/api/getPdf?pmcid=${pmcid}`;
-        const urlsToTry = [pdfUrl, europePmcUrl].filter(Boolean);
+        const urlsToTry = [ftpPdfUrl, pdfUrl, europePmcUrl].filter(Boolean);
 
         let pdfBuf: Buffer | null = null;
         let usedUrl = '';