fix(types): replace all as any with proper type assertions

Eliminate unsafe `as any` casts across 21 non-test source files,
replacing them with specific type annotations:

- Bridge transport: use StdoutMessage type for write/writeBatch calls
- print.ts: type msg.request as Record<string, unknown> for unknown
  SDK control subtypes; use StdoutMessage for output.enqueue()
- API providers (openai/grok/gemini): import ChatCompletion types,
  type streams as AsyncIterable<ChatCompletionChunk>, type request
  bodies as ChatCompletionCreateParamsStreaming
- Computer use executor: use Partial<ResolvePrepareCaptureResult>
  for cross-platform screenshot result
- Components: replace Ink color string casts with proper typing
- Win32 bridge: type stdin as Writable after null check

All 2453 tests pass with 0 failures.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/BuiltinStatusLine.tsx

@@ -55,7 +55,7 @@ function BuiltinStatusLineInner({
   // Force re-render every 60s so countdowns stay current
   const [tick, setTick] = useState(0);
   useEffect(() => {
-    const hasResetTime = rateLimits.five_hour?.resets_at || rateLimits.seven_day?.resets_at;
+    const hasResetTime = (rateLimits.five_hour?.resets_at ?? 0) || (rateLimits.seven_day?.resets_at ?? 0);
     if (!hasResetTime) return;
     const id = setInterval(() => setTick(t => t + 1), 60_000);
     return () => clearInterval(id);