Add task sidebar workflow

internal/harness/scenarios/chrome_survives_origin_mode.json

@@ -22,7 +22,7 @@
     { "type": "assert_contains", "contains": "Scratchpads" },
     {
       "type": "assert_regex",
-      "regex": "(?m)^[^\\n]*\\+ new[^\\n]*Processes[^\\n]*$"
+      "regex": "(?m)^[^\\n]*\\+ new[^\\n]*Tasks[^\\n]*$"
     },
     {
       "type": "assert_regex",

internal/harness/scenarios/create_task_and_start_agent.json

@@ -0,0 +1,42 @@
+{
+  "name": "create_task_and_start_agent",
+  "presets": {
+    "agents": [
+      {
+        "name": "fake-agent",
+        "argv": ["fake-agent"]
+      }
+    ]
+  },
+  "scripts": [
+    {
+      "name": "fake-agent",
+      "body": "#!/bin/sh\necho FAKE READY\ncat\n"
+    }
+  ],
+  "steps": [
+    { "type": "wait_stable", "timeout_ms": 3000 },
+    { "type": "assert_contains", "contains": "Tasks" },
+    { "type": "assert_contains", "contains": "Ctrl-K create task" },
+
+    { "type": "send_chord", "chord": "ctrl-k" },
+    { "type": "send_text", "text": "Create task" },
+    { "type": "send_chord", "chord": "enter" },
+    { "type": "wait_text", "contains": "Create task", "timeout_ms": 3000 },
+    { "type": "send_text", "text": "Harness task" },
+    { "type": "send_chord", "chord": "enter" },
+    { "type": "wait_text", "contains": "task: Harness task", "timeout_ms": 5000 },
+    { "type": "assert_contains", "contains": "Harness task" },
+
+    { "type": "send_chord", "chord": "ctrl-k" },
+    { "type": "send_text", "text": "fake-agent" },
+    { "type": "send_chord", "chord": "enter" },
+    { "type": "wait_text", "contains": "task_register_worktree", "timeout_ms": 8000 },
+    {
+      "type": "assert_mcp",
+      "method": "list_processes",
+      "path": "0.name",
+      "contains": "Harness task"
+    }
+  ]
+}