feat(recovery,context): tier-2 intent-holder arbiter + remaining-delta pinning + surfaced signal events

- recovery: two-tier repair ladder — owner then arbiter (recovery stage recast
  as intent-holder, holds initial intent, reconciles cross-file contract disputes)
  with independent INTENT_ROUTE_BUDGET; RecoveryRoutingTest coverage
- context: remaining-delta checklist pinning (RemainingDelta{Pinning,Entry}Test)
- surface write-only events (session name, quality signals) into stats/browse
- parseToolArguments lenient-Json fallback for bare-key drift
- tools: ChildProcess seam

apps/tui-go/internal/app/update.go

@@ -1160,6 +1160,7 @@ func paletteCommands() []paletteCmd {
 		{"rail", "", "idle rail", "show / hide the idle status + keys rail"},
 		{"panel", "d", "right panel", "in-session: events → changes → off"},
 		{"actions", "", "inline actions", "show / hide tool & action rows in output"},
+		{"thinking", "", "thinking blocks", "show / hide model reasoning in output"},
 		{"help", "?", "help", "keybinding cheat-sheet"},
 		{"mode", "s", "toggle mode", "switch chat / steering"},
 		{"cancel", "c", "cancel session", "stop the selected session"},
@@ -1217,6 +1218,9 @@ func (m Model) execPalette(id string) (tea.Model, tea.Cmd) {
 		m.cycleRightPanel()
 	case "actions":
 		m.toggleInlineActions()
+	case "thinking":
+		m.thinkingShown = !m.thinkingShown
+		saveThinkingShown(m.thinkingShown)
 	case "help":
 		m.overlay = OverlayHelp
 		m.modalScroll = 0