fix(plan): gate the immediate commit on the open-turn fold, not agent status

The TUI keyless smoke exposed the wrong idle signal: /plan submitted while
the driver is between turns still saw status running (checkpointing), so
the selection queued and the immediate copy never appeared. The commit
gate is now the log's own open-turn fold — plan/mode commits at once
whenever no turn is open, and queues only inside one. Specs drive the
distinction through explicit turn/start / turn/end events instead of a
fake status; the keyless smoke pins the new idle copy on both /plan and
/plan off; regenerated cordis/service catalogs ride along.

examples/tui-agent/tests/tui-keyless-smoke.e2e.ts

@@ -149,14 +149,14 @@ describe('tui-agent keyless smoke (real Loader tree in a PTY)', () => {
       actions: [
         { waitFor: 'main-session-', send: '/plan' },
         { waitFor: '[off|message] — Enter or leave plan mode', send: '\r' },
-        { waitFor: 'Entering plan mode (applies from the next step). Use /plan off to leave.', send: '/exit\r' },
+        { waitFor: 'Plan mode on. Use /plan off to leave.', send: '/exit\r' },
       ],
     })
     expect(output).toContain('DEEPSEEK')
     expect(output).toContain('HARNESS')
     expect(output).toContain('main-session-')
     expect(output).toContain('[off|message] — Enter or leave plan mode')
-    expect(output).toContain('Entering plan mode (applies from the next step). Use /plan off to leave.')
+    expect(output).toContain('Plan mode on. Use /plan off to leave.')
     // Borderless: no box-drawing frame around the banner.
     expect(output).not.toContain('╭')
     expect(output).not.toContain('╮')
@@ -183,15 +183,15 @@ describe('tui-agent keyless smoke (real Loader tree in a PTY)', () => {
         // Gating /status on it keeps the assertion race-free; the diagnostics
         // card is then exercised through the same real Loader/PTY composition.
         { waitFor: 'scripted session title — DeepSeek Harness', send: '/plan off\r' },
-        { waitFor: 'Leaving plan mode (applies from the next step).', send: 'Confirm the scripted run left plan mode.\r' },
+        { waitFor: 'Plan mode off.', send: 'Confirm the scripted run left plan mode.\r' },
         { waitFor: 'Default mode confirmed.', send: '/status\r' },
         { waitFor: 'Session status', send: '/exit\r' },
       ],
     })
     expect(output).toContain('I need one decision before I continue.')
     expect(output).toContain('Reasoning effort: Max.')
-    expect(output).toContain('Entering plan mode (applies from the next step). Use /plan off to leave.')
-    expect(output).toContain('Leaving plan mode (applies from the next step).')
+    expect(output).toContain('Plan mode on. Use /plan off to leave.')
+    expect(output).toContain('Plan mode off.')
     expect(output).toContain('Default mode confirmed.')
     expect(output).toContain(String.raw`\x1b]2;MODEL_CONTROLLED\x07`)
     expect(output).toContain(String.raw`\x1b[999CMODEL_CURSOR`)