Signature image in cover letter + fix per-paragraph capitalization

- Only the first body paragraph continues the salutation (lowercase safe
  opener); every following paragraph is a new sentence and is capitalized.
  Handled deterministically so it no longer depends on the model.
- Signature: upload a signature image on the Vorlagen page (preview / replace /
  remove). It is embedded in the cover letter directly under the closing
  salutation, replacing the typed name; falls back to the name when absent.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server.js

@@ -95,6 +95,48 @@ const uploadBasisAnhang = multer({
   limits: { fileSize: 15 * 1024 * 1024 }, // 15 MB
 }).single('datei');
 
+// Directory + uploader for the applicant's signature image (used in the letter)
+const signaturDir = path.join(dataDir, 'signatur');
+if (!fs.existsSync(signaturDir)) {
+  fs.mkdirSync(signaturDir, { recursive: true });
+}
+const uploadSignatur = multer({
+  storage: multer.diskStorage({
+    destination: (req, file, cb) => cb(null, signaturDir),
+    filename: (req, file, cb) => {
+      const ext = (path.extname(file.originalname) || '.png').toLowerCase();
+      cb(null, `signatur_${Date.now()}${ext}`);
+    },
+  }),
+  limits: { fileSize: 5 * 1024 * 1024 }, // 5 MB
+  fileFilter: (req, file, cb) => cb(null, /^image\/(png|jpe?g)$/.test(file.mimetype)),
+}).single('signatur');
+
+// The single stored signature file, if any.
+function currentSignaturFile() {
+  try {
+    const files = fs.readdirSync(signaturDir).filter((f) => !f.startsWith('.'));
+    return files.length ? path.join(signaturDir, files[0]) : null;
+  } catch (e) {
+    return null;
+  }
+}
+
+// Read the signature as a data URL + jsPDF format, for embedding in the letter.
+function loadSignatur() {
+  const file = currentSignaturFile();
+  if (!file) return null;
+  try {
+    const ext = path.extname(file).toLowerCase();
+    const format = (ext === '.jpg' || ext === '.jpeg') ? 'JPEG' : 'PNG';
+    const mime = format === 'JPEG' ? 'image/jpeg' : 'image/png';
+    const b64 = fs.readFileSync(file).toString('base64');
+    return { dataUrl: `data:${mime};base64,${b64}`, format };
+  } catch (e) {
+    return null;
+  }
+}
+
 // Database setup
 const dbPath = path.join(dataDir, 'bewerbungen.db');
 const db = new sqlite3.Database(dbPath);
@@ -184,6 +226,8 @@ async function runGeneration(bewerbungId) {
       zusatzAnlagen: basisAnhaenge.map((a) => a.name || a.dateiname),
       // Free-text notes (company address, contact person, extra context) for the LLM.
       llmNotizen: bewerbung.llm_notizen || '',
+      // Signature image placed under the closing salutation (instead of the typed name).
+      signatur: loadSignatur(),
     });
 
     let seq = 0;
@@ -749,6 +793,7 @@ initializeDatabase().then(() => {
       res.render('vorlagen', {
         basisDokumente,
         basisAnhaenge,
+        hasSignatur: Boolean(currentSignaturFile()),
         basisTypOptions: BASIS_TYP_OPTIONS,
         hasApiKey: Boolean(process.env.OLLAMA_API_KEY),
         hideSettings: true,
@@ -860,6 +905,42 @@ initializeDatabase().then(() => {
     }
   });
 
+  // ----- Signature (Unterschrift) -----
+
+  // Serve the current signature image (for the preview on the Vorlagen page)
+  app.get('/unterschrift', (req, res) => {
+    const file = currentSignaturFile();
+    if (!file) return res.status(404).send('Keine Unterschrift');
+    res.sendFile(file);
+  });
+
+  // Upload / replace the signature
+  app.post('/unterschrift', (req, res) => {
+    uploadSignatur(req, res, (err) => {
+      try {
+        if (err) console.error('Signature upload error:', err.message);
+        if (req.file) {
+          // keep only the newly uploaded file
+          fs.readdirSync(signaturDir).forEach((f) => {
+            if (f !== req.file.filename) fs.promises.unlink(path.join(signaturDir, f)).catch(() => {});
+          });
+        }
+        res.redirect('/vorlagen');
+      } catch (error) {
+        console.error('Error saving signature:', error);
+        res.status(500).send('Serverfehler');
+      }
+    });
+  });
+
+  // Delete the signature
+  app.post('/unterschrift/delete', (req, res) => {
+    try {
+      fs.readdirSync(signaturDir).forEach((f) => fs.promises.unlink(path.join(signaturDir, f)).catch(() => {}));
+    } catch (e) { /* ignore */ }
+    res.redirect('/vorlagen');
+  });
+
   // Download a generated attachment
   app.get('/anhaenge/:id/download', async (req, res) => {
     try {