feat(interactive): fresh-worktree-on-demand + ad-hoc launch specs

BuildForTaskAsync now creates a worktree on demand (via WorktreeManager.CreateAsync,
the same path TaskRunner uses) when a task has a configured working dir but no
Active/Kept worktree, returning a fresh-start spec -- so never-run tasks can be
opened interactively. Adds BuildForDirectoryAsync + GetAdHocLaunchSpec hub/client
for ad-hoc sessions in an arbitrary directory (no task, no worktree, no skill seeding).

src/ClaudeDo.Worker/Runner/InteractiveLaunchSpecService.cs

@@ -28,17 +28,20 @@ public sealed class InteractiveLaunchSpecService : IInteractiveLaunchSpecService
     private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
     private readonly ISessionSkillSeeder _skillSeeder;
     private readonly ISessionSkillRegistry _skillRegistry;
+    private readonly WorktreeManager _wtManager;
     private readonly string _claudePath;
 
     public InteractiveLaunchSpecService(
         IDbContextFactory<ClaudeDoDbContext> dbFactory,
         ISessionSkillSeeder skillSeeder,
         ISessionSkillRegistry skillRegistry,
+        WorktreeManager wtManager,
         WorkerConfig cfg)
     {
         _dbFactory = dbFactory;
         _skillSeeder = skillSeeder;
         _skillRegistry = skillRegistry;
+        _wtManager = wtManager;
         _claudePath = cfg.ClaudeBin;
     }
 
@@ -52,14 +55,32 @@ public sealed class InteractiveLaunchSpecService : IInteractiveLaunchSpecService
             throw new InvalidOperationException("Can't open an interactive session for a running or queued task -- interrupt it first.");
 
         var worktree = await new WorktreeRepository(ctx).GetByTaskIdAsync(taskId, ct);
+        var isFreshWorktree = false;
+
         if (worktree is null || worktree.State is not (WorktreeState.Active or WorktreeState.Kept))
-            throw new InvalidOperationException("This task has no active worktree to open a session in.");
-        if (!Directory.Exists(worktree.Path))
+        {
+            // No usable worktree yet -- if the task's list points at a git repo, create one
+            // on demand via the SAME mechanism an autonomous run uses (WorktreeManager.CreateAsync:
+            // branch naming, base commit resolution, worktree-root strategy, DB registration).
+            var list = await new ListRepository(ctx).GetByIdAsync(task.ListId, ct);
+            if (list?.WorkingDir is null)
+                throw new InvalidOperationException("This task has no working directory configured -- can't create a worktree.");
+
+            await _wtManager.CreateAsync(task, list, ct);
+            worktree = await new WorktreeRepository(ctx).GetByTaskIdAsync(taskId, ct)
+                ?? throw new InvalidOperationException("Worktree creation did not persist a worktree row.");
+            isFreshWorktree = true;
+        }
+        else if (!Directory.Exists(worktree.Path))
+        {
             throw new InvalidOperationException("The task's worktree directory no longer exists.");
+        }
 
         var listConfig = await new ListRepository(ctx).GetConfigAsync(task.ListId, ct);
         var globalSettings = await new AppSettingsRepository(ctx).GetAsync(ct);
-        var run = await new TaskRunRepository(ctx).GetLatestByTaskIdAsync(taskId, ct);
+        // A brand-new worktree has no prior session to resume, regardless of any session
+        // history the task accumulated before its previous worktree went away.
+        var run = isFreshWorktree ? null : await new TaskRunRepository(ctx).GetLatestByTaskIdAsync(taskId, ct);
 
         var requestedSkills = TaskRunner.UnionSkillNames(task.SessionSkills, listConfig?.SessionSkills, globalSettings.SessionSkills);
         var skillNames = await FilterToInstalledSkillsAsync(requestedSkills, ct);
@@ -83,6 +104,22 @@ public sealed class InteractiveLaunchSpecService : IInteractiveLaunchSpecService
         return new LaunchSpec(worktree.Path, resolvedClaude, args, env);
     }
 
+    public Task<LaunchSpec> BuildForDirectoryAsync(string directory, CancellationToken ct)
+    {
+        if (!Directory.Exists(directory))
+            throw new InvalidOperationException($"Directory does not exist: {directory}");
+
+        var resolvedClaude = WindowsTerminalLauncher.Resolve(_claudePath)
+            ?? throw new InvalidOperationException($"claude executable not found: {_claudePath}");
+
+        var env = new Dictionary<string, string>
+        {
+            ["MCP_TOOL_TIMEOUT"] = "200000",
+        };
+
+        return Task.FromResult(new LaunchSpec(directory, resolvedClaude, Array.Empty<string>(), env));
+    }
+
     private async Task<IReadOnlyList<string>> FilterToInstalledSkillsAsync(IReadOnlyList<string> requested, CancellationToken ct)
     {
         if (requested.Count == 0) return requested;

src/ClaudeDo.Worker/Runner/Interfaces/IInteractiveLaunchSpecService.cs

@@ -2,9 +2,17 @@ namespace ClaudeDo.Worker.Runner;
 
 public interface IInteractiveLaunchSpecService
 {
-    /// <summary>Builds a LaunchSpec for opening an interactive session in an existing task's
-    /// worktree. Throws KeyNotFoundException if the task doesn't exist, InvalidOperationException
-    /// if it's Running/Queued or has no usable worktree. A task that has never run (no persisted
-    /// SessionId) is not an error -- the spec omits --resume for a fresh start.</summary>
+    /// <summary>Builds a LaunchSpec for opening an interactive session in a task's worktree.
+    /// Throws KeyNotFoundException if the task doesn't exist, InvalidOperationException
+    /// if it's Running/Queued. If the task has no usable worktree yet, one is created on
+    /// demand (same mechanism as an autonomous run) provided the task's list has a working
+    /// directory pointing at a git repo -- otherwise throws InvalidOperationException. A task
+    /// that has never run, or whose worktree was just created fresh, gets a fresh-start spec
+    /// (no --resume); an existing worktree with a persisted SessionId gets --resume.</summary>
     Task<LaunchSpec> BuildForTaskAsync(string taskId, CancellationToken ct);
+
+    /// <summary>Builds a LaunchSpec for an ad-hoc interactive session in an arbitrary directory --
+    /// no task, no worktree, no session-skills seeding. Throws InvalidOperationException if the
+    /// directory doesn't exist.</summary>
+    Task<LaunchSpec> BuildForDirectoryAsync(string directory, CancellationToken ct);
 }