feat(tui): honor display.* flags in turn renderer, status bar, and event handler

- turnController gates scheduleStreaming / reasoning recorders on
  streaming + showReasoning so disabling them keeps the buffer silent
  until message.complete flushes
- createGatewayEventHandler only surfaces inline_diff previews when
  inlineDiffs is on
- StatusRule takes a showCost prop and renders `· $X.XXXX` with the
  same toFixed(4) formatting as /usage when usage.cost_usd is present
- Usage grows cost_usd?: number to match the gateway payload
- Existing handler tests flip showReasoning on in beforeEach so
  reasoning-flow assertions keep their meaning

ui-tui/src/__tests__/createGatewayEventHandler.test.ts

@@ -4,7 +4,7 @@ import { createGatewayEventHandler } from '../app/createGatewayEventHandler.js'
 import { resetOverlayState } from '../app/overlayStore.js'
 import { turnController } from '../app/turnController.js'
 import { resetTurnState } from '../app/turnStore.js'
-import { resetUiState } from '../app/uiStore.js'
+import { patchUiState, resetUiState } from '../app/uiStore.js'
 import { estimateTokensRough } from '../lib/text.js'
 import type { Msg } from '../types.js'
 
@@ -47,6 +47,7 @@ describe('createGatewayEventHandler', () => {
     resetUiState()
     resetTurnState()
     turnController.fullReset()
+    patchUiState({ showReasoning: true })
   })
 
   it('persists completed tool rows when message.complete lands immediately after tool.complete', () => {

ui-tui/src/app/createGatewayEventHandler.ts

@@ -266,7 +266,7 @@ export function createGatewayEventHandler(ctx: GatewayEventHandlerContext): (ev:
       case 'tool.complete':
         turnController.recordToolComplete(ev.payload.tool_id, ev.payload.name, ev.payload.error, ev.payload.summary)
 
-        if (ev.payload.inline_diff) {
+        if (ev.payload.inline_diff && getUiState().inlineDiffs) {
           sys(ev.payload.inline_diff)
         }
 

ui-tui/src/app/turnController.ts

@@ -11,7 +11,7 @@ import type { ActiveTool, ActivityItem, Msg, SubagentProgress } from '../types.j
 
 import { resetOverlayState } from './overlayStore.js'
 import { patchTurnState, resetTurnState } from './turnStore.js'
-import { patchUiState } from './uiStore.js'
+import { getUiState, patchUiState } from './uiStore.js'
 
 const INTERRUPT_COOLDOWN_MS = 1500
 const ACTIVITY_LIMIT = 8
@@ -226,10 +226,17 @@ class TurnController {
     }
 
     this.bufRef = rendered ?? this.bufRef + text
-    this.scheduleStreaming()
+
+    if (getUiState().streaming) {
+      this.scheduleStreaming()
+    }
   }
 
   recordReasoningAvailable(text: string) {
+    if (!getUiState().showReasoning) {
+      return
+    }
+
     const incoming = text.trim()
 
     if (!incoming || this.reasoningText.trim()) {
@@ -242,6 +249,10 @@ class TurnController {
   }
 
   recordReasoningDelta(text: string) {
+    if (!getUiState().showReasoning) {
+      return
+    }
+
     this.reasoningText += text
     this.scheduleReasoning()
     this.pulseReasoningStreaming()

ui-tui/src/components/appChrome.tsx

@@ -99,6 +99,7 @@ export function StatusRule({
   usage,
   bgCount,
   sessionStartedAt,
+  showCost,
   voiceLabel,
   t
 }: StatusRuleProps) {
@@ -136,6 +137,9 @@ export function StatusRule({
           ) : null}
           {voiceLabel ? <Text color={t.color.dim}> │ {voiceLabel}</Text> : null}
           {bgCount > 0 ? <Text color={t.color.dim}> │ {bgCount} bg</Text> : null}
+          {showCost && typeof usage.cost_usd === 'number' ? (
+            <Text color={t.color.dim}> │ ${usage.cost_usd.toFixed(4)}</Text>
+          ) : null}
         </Text>
       </Box>
 
@@ -285,6 +289,7 @@ interface StatusRuleProps {
   cwdLabel: string
   model: string
   sessionStartedAt?: number | null
+  showCost: boolean
   status: string
   statusColor: string
   t: Theme

ui-tui/src/components/appLayout.tsx

@@ -190,6 +190,7 @@ const ComposerPane = memo(function ComposerPane({
             cwdLabel={status.cwdLabel}
             model={ui.info?.model?.split('/').pop() ?? ''}
             sessionStartedAt={status.sessionStartedAt}
+            showCost={ui.showCost}
             status={ui.status}
             statusColor={status.statusColor}
             t={ui.theme}

ui-tui/src/types.ts

@@ -68,6 +68,7 @@ export interface Usage {
   context_max?: number
   context_percent?: number
   context_used?: number
+  cost_usd?: number
   input: number
   output: number
   total: number