feat(interactive): seed fresh task session with the task prompt

A fresh (non-resume) task-based ConPTY session now opens claude on the task's
prompt (title + description) as the positional argument, so the session starts on
the task instead of an empty prompt. Resume sessions and ad-hoc sessions are
unchanged.

src/ClaudeDo.Worker/Runner/InteractiveLaunchSpecService.cs

@@ -89,9 +89,12 @@ public sealed class InteractiveLaunchSpecService : IInteractiveLaunchSpecService
         var resolvedClaude = WindowsTerminalLauncher.Resolve(_claudePath)
             ?? throw new InvalidOperationException($"claude executable not found: {_claudePath}");
 
+        // Resume an existing session as-is; for a fresh session, seed the interactive TUI with
+        // the task's prompt (title + description) as claude's positional prompt so it starts on
+        // the task -- the user then supervises/answers rather than retyping it.
         var args = run?.SessionId is { Length: > 0 } sessionId
             ? WindowsTerminalLauncher.BuildResumeArgs(sessionId)
-            : Array.Empty<string>();
+            : BuildFreshPromptArgs(task);
 
         // Same run environment variable ClaudeProcess sets for every headless run: the
         // AskUser MCP tool call caps at 60s unless raised, and lifting it is harmless for
@@ -120,6 +123,22 @@ public sealed class InteractiveLaunchSpecService : IInteractiveLaunchSpecService
         return Task.FromResult(new LaunchSpec(directory, resolvedClaude, Array.Empty<string>(), env));
     }
 
+    // The positional prompt claude opens the interactive session on. Empty (no positional arg)
+    // if the task has neither a title nor a description.
+    private static IReadOnlyList<string> BuildFreshPromptArgs(TaskEntity task)
+    {
+        var title = task.Title?.Trim();
+        var description = task.Description?.Trim();
+        var prompt = (string.IsNullOrEmpty(title), string.IsNullOrEmpty(description)) switch
+        {
+            (false, false) => $"{title}\n\n{description}",
+            (false, true) => title!,
+            (true, false) => description!,
+            _ => string.Empty,
+        };
+        return string.IsNullOrEmpty(prompt) ? Array.Empty<string>() : new[] { prompt };
+    }
+
     private async Task<IReadOnlyList<string>> FilterToInstalledSkillsAsync(IReadOnlyList<string> requested, CancellationToken ct)
     {
         if (requested.Count == 0) return requested;

tests/ClaudeDo.Worker.Tests/Runner/InteractiveLaunchSpecServiceTests.cs

@@ -181,7 +181,7 @@ public sealed class InteractiveLaunchSpecServiceTests : IDisposable
         Assert.True(Directory.Exists(wtRow.Path));
 
         Assert.Equal(wtRow.Path, spec.Cwd);
-        Assert.Empty(spec.Args);
+        Assert.Equal(new[] { "T" }, spec.Args); // fresh session seeds the task title as the prompt
         Assert.Equal(_claudeStubPath, spec.Exe);
     }
 
@@ -258,7 +258,7 @@ public sealed class InteractiveLaunchSpecServiceTests : IDisposable
         var svc = BuildService();
         var spec = await svc.BuildForTaskAsync(taskId, CancellationToken.None);
 
-        Assert.Empty(spec.Args);
+        Assert.Equal(new[] { "T" }, spec.Args); // fresh: seeds the task title as the prompt
         Assert.Equal(_worktreeDir, spec.Cwd);
     }
 
@@ -274,7 +274,27 @@ public sealed class InteractiveLaunchSpecServiceTests : IDisposable
         var svc = BuildService();
         var spec = await svc.BuildForTaskAsync(taskId, CancellationToken.None);
 
-        Assert.Empty(spec.Args);
+        Assert.Equal(new[] { "T" }, spec.Args); // fresh: seeds the task title as the prompt
+    }
+
+    [Fact]
+    public async Task BuildForTaskAsync_FreshTask_WithDescription_SeedsTitleAndDescriptionPrompt()
+    {
+        var listId = await SeedListAsync();
+        var taskId = Guid.NewGuid().ToString();
+        await SeedTaskAsync(taskId, listId, TaskStatus.Idle);
+        await SeedWorktreeAsync(taskId, WorktreeState.Active);
+        using (var ctx = _db.CreateContext())
+        {
+            var t = await ctx.Tasks.FindAsync(taskId);
+            t!.Description = "Do the thing";
+            await ctx.SaveChangesAsync();
+        }
+
+        var svc = BuildService();
+        var spec = await svc.BuildForTaskAsync(taskId, CancellationToken.None);
+
+        Assert.Equal(new[] { "T\n\nDo the thing" }, spec.Args);
     }
 
     [Fact]