Add accountant/investor skills, Excel editor, email attachment fixes

Skills:
- Add accountant (CPA) and investor (CFA) skills with site: hints
- Add site: hints to lawyer, psychiatrist, musician skills
- Allow multiple skills active simultaneously (remove exclusive mode)

Tools:
- Add excel_read / excel_write tools (openpyxl-based)
- Fix python_eval packages: retry with --break-system-packages on PEP 668 failure
- Fix email_read: spaces→underscores in filenames, return /api/files/ links,
  remove absolute savedPaths from data, send SSE 'files' event for attachments

Server:
- FILE_OP v2: fall through to primary when secondary model unavailable
- Add PUT /api/files/{*filePath} endpoint for xlsx editor save

UI:
- xlsx viewer: Luckysheet modal (lazy CDN load, ~3MB on first use)
  with edit mode, 💾 save button, Nanum Gothic font
- Email attachment preview: SSE 'files' event appends file links to final reply
- ✏️ 편집 button (blue) for xlsx cards

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

src/tools/email.ts

@@ -364,7 +364,7 @@ export const emailReadTool = {
               fs.mkdirSync(saveDir, { recursive: true });
               for (const att of parsed.attachments) {
                 const filename = att.filename || `attachment-${savedPaths.length + 1}`;
-                const safeName = filename.replace(/[/\\:*?"<>|]/g, '_');
+                const safeName = filename.replace(/[/\\:*?"<>|]/g, '_').replace(/\s+/g, '_');
                 const dest = path.join(saveDir, safeName);
                 fs.writeFileSync(dest, att.content);
                 savedPaths.push(dest);
@@ -410,13 +410,14 @@ export const emailReadTool = {
           `날짜: ${r.date}`,
           r.attachments.length ? `첨부파일: ${r.attachments.join(', ')}` : '',
           r.savedRelPaths?.length
-            ? `✅ 첨부파일 저장 완료 — pdf_read/read 등에서 아래 경로를 그대로 사용하세요:\n${r.savedRelPaths.map((p: string) => `  "${p}"`).join('\n')}`
+            ? `✅ 첨부파일 저장 완료 — pdf_read 등에서 아래 상대경로를 그대로 사용하세요:\n${r.savedRelPaths.map((p: string) => `  - [${path.basename(p)}](/api/files/${p.replace(/\\/g, '/')})`).join('\n')}`
             : '',
           '',
           '─── 본문 ───',
           r.body,
         ].filter((l: string) => l !== '');
-        return { success: true, stdout: lines.join('\n'), data: { ...r, account: found.account } };
+        const { savedPaths: _sp, ...safeData } = { ...r, account: found.account };
+        return { success: true, stdout: lines.join('\n'), data: safeData };
       }
 
       // No account specified — try all accounts
@@ -438,13 +439,14 @@ export const emailReadTool = {
             `날짜: ${r.date}`,
             r.attachments.length ? `첨부파일: ${r.attachments.join(', ')}` : '',
             r.savedRelPaths?.length
-              ? `✅ 첨부파일 저장 완료 — pdf_read/read 등에서 아래 경로를 그대로 사용하세요:\n${r.savedRelPaths.map((p: string) => `  "${p}"`).join('\n')}`
+              ? `✅ 첨부파일 저장 완료 — pdf_read 등에서 아래 상대경로를 그대로 사용하세요:\n${r.savedRelPaths.map((p: string) => `  - [${path.basename(p)}](/api/files/${p.replace(/\\/g, '/')})`).join('\n')}`
               : '',
             '',
             '─── 본문 ───',
             r.body,
           ].filter((l: string) => l !== '');
-          return { success: true, stdout: lines.join('\n'), data: { ...r, account: found.account } };
+          const { savedPaths: _sp, ...safeData } = { ...r, account: found.account };
+          return { success: true, stdout: lines.join('\n'), data: safeData };
         }
         errors.push(acct.id);
       }