opentui(harden): fix 3 triaged findings (timer leak, tool-match scope, complete-only)

Subagent hardening pass over boundary/logic/view, findings triaged (most were
false positives or app-lifetime-moot). The 3 genuine fixes:
- liveGateway.stop() now clears the pending 16ms coalesce timer before
  client.stop() — a queued flush() could otherwise fire batch()/handlers into a
  torn-down store after the layer scope releases.
- store.findToolPart now scans only the LIVE (last) assistant turn, not every
  message — a tool.complete pairs with a tool.start in the current turn, so this
  avoids matching a same-id tool in an older/resumed turn (and is O(parts)).
- store message.complete with text but NO prior start/delta now creates the turn
  (complete-only gateways) instead of dropping the final text; still no empty
  bubble when there's no text. +2 regression tests.

Triaged as NOT-a-bug / accepted-risk (documented so they're not relitigated):
@opentui/solid useKeyboard DOES auto-cleanup (onCleanup keyHandler.off, index.js:59);
dimensions/scrollAnchor timers are app-lifetime / try-catch-safe; unbounded-growth,
duplicate-dedup, and split-frame are theoretical for a trusted local newline-framed
subprocess; clipboard spawn timeout + atomic active-session write are minor follow-ups.
93 pass.

ui-tui-opentui-v2/src/boundary/gateway/liveGateway.ts

@@ -113,7 +113,14 @@ function makeLiveGateway(): { service: GatewayServiceShape; stop: () => void } {
     sessionId: () => sessionId
   }
 
-  return { service, stop: () => client.stop() }
+  // Clear a pending coalesce timer on teardown so a queued flush() can't fire
+  // batch()/handlers into a torn-down store after the layer scope releases.
+  const stop = () => {
+    if (timer) clearTimeout(timer)
+    timer = undefined
+    client.stop()
+  }
+  return { service, stop }
 }
 
 /**

ui-tui-opentui-v2/src/logic/store.ts

@@ -323,15 +323,15 @@ export function createSessionStore() {
     return created
   }
 
-  /** Find a tool part by id, scanning recent assistant turns (complete may land late). */
+  /** Find a tool part by id in the CURRENT (last) assistant turn — a tool.complete
+   *  always pairs with a tool.start in the live turn, so scoping there avoids
+   *  matching a same-id tool in an older/resumed turn (and is O(parts), not O(all)). */
   function findToolPart(draft: StoreState, id: string): ToolPartState | undefined {
-    for (let i = draft.messages.length - 1; i >= 0; i--) {
-      const parts = draft.messages[i]?.parts
-      if (!parts) continue
-      for (let j = parts.length - 1; j >= 0; j--) {
-        const p = parts[j]
-        if (p && p.type === 'tool' && p.id === id) return p
-      }
+    const parts = liveAssistant(draft)?.parts
+    if (!parts) return undefined
+    for (let j = parts.length - 1; j >= 0; j--) {
+      const p = parts[j]
+      if (p && p.type === 'tool' && p.id === id) return p
     }
     return undefined
   }
@@ -473,10 +473,12 @@ export function createSessionStore() {
       case 'message.complete':
         setState(
           produce(draft => {
-            const live = liveAssistant(draft, true)
+            // complete-only gateways may send `message.complete{text}` with no prior
+            // start/delta → create the turn so the final text isn't dropped.
+            const finalText = event.payload?.text
+            const live = liveAssistant(draft, true) ?? (finalText ? ensureAssistant(draft) : undefined)
             if (!live) return
             // If no deltas arrived (complete-only gateways), seed the full text once.
-            const finalText = event.payload?.text
             const hasText = (live.parts ?? []).some(p => p.type === 'text' && p.text.length > 0)
             if (finalText && !hasText) appendPart(live, 'text', finalText)
             live.streaming = false

ui-tui-opentui-v2/src/test/store.test.ts

@@ -91,6 +91,24 @@ describe('session store — ordered parts (Phase 2b)', () => {
     }
   })
 
+  test('message.complete with text but NO prior start creates the turn (complete-only gateway; no drop)', () => {
+    const store = createSessionStore()
+    store.apply({ type: 'gateway.ready' })
+    // no message.start / no deltas — straight to complete with the full text
+    store.apply({ type: 'message.complete', payload: { text: 'The whole answer.' } })
+    const msg = store.state.messages.at(-1)!
+    expect(msg.role).toBe('assistant')
+    expect(msg.streaming).toBe(false)
+    expect(msg.parts?.some(p => p.type === 'text' && p.text === 'The whole answer.')).toBe(true)
+  })
+
+  test('message.complete with no live turn and no text does NOT create an empty bubble', () => {
+    const store = createSessionStore()
+    store.apply({ type: 'gateway.ready' })
+    store.apply({ type: 'message.complete', payload: {} })
+    expect(store.state.messages.filter(m => m.role === 'assistant')).toHaveLength(0)
+  })
+
   test('tool.complete updates the running tool part IN PLACE (not a new row)', () => {
     const store = createSessionStore()
     store.apply({ type: 'message.start' })