fix: show structured-output summary instead of raw JSON in OUTCOME

A --json-schema run can echo the structured {"summary":...} JSON as the
result text, which then landed verbatim in task.Result and rendered raw in
the OUTCOME card. Unwrap the summary in StreamAnalyzer when the result text
is itself such a JSON object (a plain markdown result is kept as-is), and
add a UI safety net in ApplyOutcome for rows already persisted as raw JSON.

src/ClaudeDo.Worker/Runner/StreamAnalyzer.cs

@@ -91,16 +91,34 @@ public sealed class StreamAnalyzer
 
     private string? FallbackResult()
     {
+        // A --json-schema run sometimes echoes the structured JSON as the result text; unwrap
+        // that to its summary. A plain markdown result is kept verbatim (even when a separate
+        // structured_output is also present). Only when there is no result text do we fall back
+        // to the structured summary, then the raw JSON.
+        if (SummaryFromJson(_resultMarkdown) is { } fromResult) return fromResult;
         if (!string.IsNullOrEmpty(_resultMarkdown)) return _resultMarkdown;
-        if (_structuredOutputJson is null) return _resultMarkdown;
+        if (SummaryFromJson(_structuredOutputJson) is { } fromStructured) return fromStructured;
+        return _structuredOutputJson;
+    }
+
+    /// <summary>Extracts a non-empty string <c>summary</c> from a JSON object, or null when
+    /// the input isn't such an object (a plain markdown result parses to null and is kept).</summary>
+    private static string? SummaryFromJson(string? json)
+    {
+        if (string.IsNullOrWhiteSpace(json)) return null;
         try
         {
-            using var doc = JsonDocument.Parse(_structuredOutputJson);
-            if (doc.RootElement.TryGetProperty("summary", out var s))
-                return s.GetString();
+            using var doc = JsonDocument.Parse(json);
+            if (doc.RootElement.ValueKind == JsonValueKind.Object &&
+                doc.RootElement.TryGetProperty("summary", out var s) &&
+                s.ValueKind == JsonValueKind.String)
+            {
+                var text = s.GetString();
+                return string.IsNullOrWhiteSpace(text) ? null : text;
+            }
         }
         catch { }
-        return _structuredOutputJson;
+        return null;
     }
 
     private void CollectFromAssistant(JsonElement root)