Add functionality to convert text to Markdown using Ollama API

src/App.tsx

@@ -581,6 +581,82 @@ export default function App() {
     setHistoryItems(combined);
   }, [historyOpen, selectedTextId]);
 
+  const handleConvertToMarkdown = useCallback(async () => {
+    if (!selectedTextId || !hasText || isViewingHistory || isConverting) return;
+    if (!ollamaModel) {
+      setConfirmState({
+        title: "Ollama",
+        message: "Select an Ollama model first.",
+        actionLabel: "OK",
+        onConfirm: () => {}
+      });
+      return;
+    }
+    const prompt = (ollamaPrompt || DEFAULT_OLLAMA_PROMPT).trim();
+    const fullPrompt = `${prompt}\n${body}`;
+    setIsConverting(true);
+    try {
+      const response = await fetch(`${normalizedOllamaUrl}/api/generate`, {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({
+          model: ollamaModel,
+          prompt: fullPrompt,
+          stream: false
+        })
+      });
+      if (!response.ok) {
+        throw new Error(`Ollama responded with ${response.status}`);
+      }
+      const data = await response.json();
+      const resultText = typeof data?.response === "string" ? data.response : "";
+      if (!resultText) {
+        throw new Error("Ollama returned an empty response.");
+      }
+      const normalizedTitle = title.trim() || DEFAULT_TITLE;
+      const result = await saveManualVersion(
+        selectedTextId,
+        normalizedTitle,
+        resultText
+      );
+      setBody(resultText);
+      setLastPersistedBody(resultText);
+      setLastPersistedTitle(normalizedTitle);
+      setHasDraft(false);
+      setRestoredDraft(false);
+      setLatestManualVersionId(result.versionId);
+      setDraftBaseVersionId(result.versionId);
+      setSelectedHistoryId(result.versionId);
+      setViewingVersion(null);
+      historySnapshotRef.current = null;
+      setMarkdownPreview(true);
+      await refreshTexts();
+      await refreshVersions();
+    } catch (error) {
+      console.error("Failed to convert with Ollama", error);
+      setConfirmState({
+        title: "Ollama error",
+        message: error instanceof Error ? error.message : "Conversion failed.",
+        actionLabel: "OK",
+        onConfirm: () => {}
+      });
+    } finally {
+      setIsConverting(false);
+    }
+  }, [
+    body,
+    hasText,
+    isConverting,
+    isViewingHistory,
+    normalizedOllamaUrl,
+    ollamaModel,
+    ollamaPrompt,
+    refreshTexts,
+    refreshVersions,
+    selectedTextId,
+    title
+  ]);
+
   useEffect(() => {
     refreshTexts().catch((error) => {
       console.error("Failed to load texts", error);