Add idle-state classifier and Solo-parity timer tools

Classifies every running child as idle/working/thinking/permission/error
using one of three pluggable strategies (output_activity,
osc_title_stability, osc_title_status) plus optional regex promoters
applied to the tail of recent output. State and last-match reason are
exposed via MCP on ProcessInfo and get_process_status. Per-preset
configuration lives on a new preset.IdleDetection block with bundled
defaults for the first-party claude/codex/opencode presets.

OSC title plumbing is exposed as Emulator.Title(), polled from the
session pump after each emulator write so title-change activity feeds
into the classifier without an extra cgo callback.

The MCP timer surface expands to match Solo: timer_set,
timer_fire_when_idle_any/all, timer_cancel, timer_pause, timer_resume,
timer_list. timer_wait is now a thin wrapper that shares the same
manager so it shows up in timer_list while pending. Timer bodies are
delivered to the owner process through the existing
InjectAsOrchestrator path. Top-level (non-agent) callers can attach
timers to a specific process via owner_process_id; omitting it grants
universal cancel/pause/resume/list privileges.

The sidebar gains a state glyph per process row and appends a
nearest-timer indicator when one is pending or paused.

Tests: idle_test.go covers the classify() pure function across the
three strategies and regex promotion; timers_test.go covers the
manager. Harness scenarios cover output_activity, osc_title_stability,
osc_title_status, and regex promotion, plus timer_set delivery,
cancel, pause/resume, idle_any-on-transition, idle_all-pending, and
idle_all-already-satisfied. A new wait_until_mcp harness step type
polls an MCP method until an assertion holds.

internal/app/launch.go

@@ -140,6 +140,7 @@ func (l *Launcher) LaunchAgent(p *preset.Preset, displayName, initialPrompt, par
 		cleanup()
 		return nil, err
 	}
+	c.setIdleDetection(resolveIdleDetection(p.IdleDetection))
 
 	// Wait for the preset's ready signal, then type the initial prompt.
 	idle := time.Duration(1000) * time.Millisecond
@@ -171,7 +172,7 @@ func (l *Launcher) LaunchCommandPreset(p *preset.Preset, displayName, parentID s
 		env = append(env, k+"="+v)
 	}
 	cols, rows := l.size()
-	return l.sess.Spawn(SpawnSpec{
+	c, err := l.sess.Spawn(SpawnSpec{
 		Kind:      KindCommand,
 		Argv:      p.ResolvedArgv(),
 		Env:       env,
@@ -180,6 +181,11 @@ func (l *Launcher) LaunchCommandPreset(p *preset.Preset, displayName, parentID s
 		WorkDir:   p.WorkingDir,
 		PresetRef: p.Name,
 	}, cols, rows)
+	if err != nil {
+		return nil, err
+	}
+	c.setIdleDetection(resolveIdleDetection(p.IdleDetection))
+	return c, nil
 }
 
 // LaunchCommandArgv spawns a freeform-argv command entry. Trust gating