feat(interactive): worker launch-spec for embedded ConPTY sessions

Adds InteractiveLaunchSpecService + GetInteractiveLaunchSpec hub method that
prepares a task worktree (session-skills seeding, run env) and returns a
LaunchSpec {cwd,exe,args,env} for a UI-hosted ConPTY terminal. Reuses
ISessionSkillSeeder, TaskRunner.UnionSkillNames, and WindowsTerminalLauncher
resume-arg/resolve logic. Guards mirror ResumeTaskInTerminal; a never-run task
yields a fresh-start spec instead of an error.

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -130,6 +130,7 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
     private readonly InteractiveSessionService _interactive;
     private readonly LogRingBuffer? _logBuffer;
     private readonly ISessionSkillRegistry _skillRegistry;
+    private readonly IInteractiveLaunchSpecService? _interactiveLaunchSpec;
 
     public WorkerHub(
         QueueService queue,
@@ -157,7 +158,8 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         Runner.PendingQuestionRegistry pendingQuestions,
         InteractiveSessionService interactive,
         ISessionSkillRegistry skillRegistry,
-        LogRingBuffer? logBuffer = null)
+        LogRingBuffer? logBuffer = null,
+        IInteractiveLaunchSpecService? interactiveLaunchSpec = null)
     {
         _queue = queue;
         _waker = waker;
@@ -185,6 +187,7 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         _interactive = interactive;
         _skillRegistry = skillRegistry;
         _logBuffer = logBuffer;
+        _interactiveLaunchSpec = interactiveLaunchSpec;
     }
 
     // Persistence boundary for the session_skills JSON-array columns (task/list/global).
@@ -657,6 +660,17 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         }
     });
 
+    // Builds the launch spec an embedded ConPTY terminal (UI process) needs to open an
+    // interactive Claude session in a task's worktree -- same worktree prep as an
+    // autonomous run (session-skills seeding, run env vars), --resume if the task has a
+    // persisted session or a fresh-start spec otherwise. Guards mirror ResumeTaskInTerminal.
+    public Task<LaunchSpec> GetInteractiveLaunchSpec(string taskId) => HubGuard(() =>
+    {
+        if (_interactiveLaunchSpec is null)
+            throw new InvalidOperationException("Interactive launch spec service is not configured.");
+        return _interactiveLaunchSpec.BuildForTaskAsync(taskId, Context.ConnectionAborted);
+    });
+
     public Task SendInteractiveMessage(string taskId, string text) =>
         _interactive.SendAsync(taskId, text, Context.ConnectionAborted);