fix(tickets): convert ticket HTML to markdown on import

src/ClaudeDo.Worker/Tickets/TicketImportService.cs

@@ -1,3 +1,5 @@
+using System.Net;
+using System.Text.RegularExpressions;
 using ClaudeDo.Data;
 using ClaudeDo.Data.Models;
 using ClaudeDo.Data.Repositories;
@@ -73,7 +75,7 @@ public sealed class TicketImportService
             {
                 Id = taskId,
                 ListId = listId,
-                Title = ticket.Title,
+                Title = WebUtility.HtmlDecode(ticket.Title).Trim(),
                 Description = BuildDescription(ticket),
                 Status = TaskStatus.Idle,
                 CreatedAt = DateTime.UtcNow,
@@ -102,7 +104,43 @@ public sealed class TicketImportService
 
     private static string BuildDescription(TicketBoardItem ticket)
     {
-        var body = string.IsNullOrWhiteSpace(ticket.Description) ? "" : ticket.Description.Trim() + "\n\n";
-        return body + $"Ticket #{ticket.Id}";
+        var body = string.IsNullOrWhiteSpace(ticket.Description) ? "" : HtmlToMarkdown(ticket.Description);
+        return (body.Length > 0 ? body + "\n\n" : "") + $"Ticket #{ticket.Id}";
+    }
+
+    private const RegexOptions Rx = RegexOptions.IgnoreCase | RegexOptions.Singleline;
+
+    /// <summary>
+    /// Wandelt das Rich-Text-HTML des Ticketsystems in das Markdown-Subset von <c>MarkdownView</c>.
+    /// Zeilenumbrüche werden zu Absätzen, weil <c>MarkdownView</c> einfache Umbrüche zusammenzieht.
+    /// </summary>
+    // ponytail: Regex statt HTML-Parser — verschachtelte Listen und Tabellen werden flach; AngleSharp, falls die Tickets das brauchen
+    internal static string HtmlToMarkdown(string html)
+    {
+        var s = Regex.Replace(html, @"\s*\r?\n\s*", " ");
+        s = Regex.Replace(s, @"<(script|style)\b.*?</\1>", "", Rx);
+        s = Regex.Replace(s, @"<h([1-6])\b[^>]*>(.*?)</h\1>",
+            m => $"\n\n{new string('#', Math.Min(int.Parse(m.Groups[1].Value), 3))} {m.Groups[2].Value}\n\n", Rx);
+        s = Regex.Replace(s, @"<(b|strong)\b[^>]*>(.*?)</\1>", m => Wrap(m.Groups[2].Value, "**"), Rx);
+        s = Regex.Replace(s, @"<(i|em)\b[^>]*>(.*?)</\1>", m => Wrap(m.Groups[2].Value, "*"), Rx);
+        s = Regex.Replace(s, @"<code\b[^>]*>(.*?)</code>", m => Wrap(m.Groups[1].Value, "`"), Rx);
+        s = Regex.Replace(s, @"<a\b[^>]*href=""([^""]*)""[^>]*>(.*?)</a>",
+            m => m.Groups[2].Value == m.Groups[1].Value ? m.Groups[1].Value : $"{m.Groups[2].Value} ({m.Groups[1].Value})", Rx);
+        s = Regex.Replace(s, @"<ol\b[^>]*>(.*?)</ol>", m =>
+        {
+            var n = 0;
+            return "\n\n" + Regex.Replace(m.Groups[1].Value, @"<li\b[^>]*>", _ => $"\n{++n}. ", Rx) + "\n\n";
+        }, Rx);
+        s = Regex.Replace(s, @"<li\b[^>]*>", "\n- ", Rx);
+        s = Regex.Replace(s, @"</?(ul|ol)\b[^>]*>", "\n\n", Rx);
+        s = Regex.Replace(s, @"<br\s*/?>|</?(p|div|blockquote|tr)\b[^>]*>", "\n\n", Rx);
+        s = Regex.Replace(s, @"<[^>]+>", "");
+        s = WebUtility.HtmlDecode(s).Replace((char)0xA0, ' ');
+
+        var lines = s.Split('\n').Select(l => Regex.Replace(l, @"[ \t]+", " ").Trim());
+        return Regex.Replace(string.Join('\n', lines), @"\n{3,}", "\n\n").Trim();
+
+        static string Wrap(string inner, string mark)
+            => string.IsNullOrWhiteSpace(inner) ? inner : $"{mark}{inner.Trim()}{mark}";
     }
 }

tests/ClaudeDo.Worker.Tests/Tickets/TicketHtmlToMarkdownTests.cs

@@ -0,0 +1,30 @@
+using ClaudeDo.Worker.Tickets;
+
+namespace ClaudeDo.Worker.Tests.Tickets;
+
+public sealed class TicketHtmlToMarkdownTests
+{
+    [Fact]
+    public void Paragraphs_breaks_and_entities_become_markdown_paragraphs()
+    {
+        var md = TicketImportService.HtmlToMarkdown(
+            "<p>Lager -&gt; Adressprüfung&nbsp;aus</p>Zeile 1<br>Zeile 2<div><br></div><div>Ende</div>");
+
+        Assert.Equal("Lager -> Adressprüfung aus\n\nZeile 1\n\nZeile 2\n\nEnde", md);
+    }
+
+    [Fact]
+    public void Lists_and_inline_formatting_map_to_the_MarkdownView_subset()
+    {
+        var md = TicketImportService.HtmlToMarkdown(
+            "<p>Offene Punkte:</p><ul><li class=\"MsoNormal\"><b>Band</b> sync</li><li>Waage</li></ul>" +
+            "<ol><li>Erst</li><li><em>Dann</em></li></ol><a href=\"http://x\">Link</a>");
+
+        Assert.Equal(
+            "Offene Punkte:\n\n- **Band** sync\n- Waage\n\n1. Erst\n2. *Dann*\n\nLink (http://x)", md);
+    }
+
+    [Fact]
+    public void Plain_text_passes_through()
+        => Assert.Equal("Ticket ohne HTML", TicketImportService.HtmlToMarkdown("  Ticket ohne HTML "));
+}