perf(cf): reduce checkbox poll interval from 200ms to 50ms (#130)

DOM.getDocument is ~2-6ms, so 50ms polling is well within margin.
Saves ~75ms avg per scrape on checkbox cold start detection.
At millions of scrapes this adds up to real hours saved.

MAX_CHECKBOX_POLLS increased from 16 to 64 to maintain the same
3.2s total wait window.

Author: DivMode

src/session/cf/cf-schedules.ts

@@ -79,13 +79,14 @@ export const OOPIF_POLL_DELAY = '200 millis' as const;
  * preventing stale/closing OOPIFs from blocking for the 30s CDP default. */
 export const OOPIF_PROBE_TIMEOUT = '3 seconds' as const;
 
-/** Phase 3 checkbox polling: max attempts. */
-export const MAX_CHECKBOX_POLLS = 16;
+/** Phase 3 checkbox polling: max attempts.
+ * 64 × 50ms = 3.2s total window (same as previous 16 × 200ms). */
+export const MAX_CHECKBOX_POLLS = 64;
 
 /** Phase 3 checkbox polling: interval between attempts (ms).
- * Reduced from 500 to 200 — DOM.getDocument is ~2-6ms, so 200ms gives
- * plenty of margin while detecting the checkbox 2.5x faster. */
-export const CHECKBOX_POLL_INTERVAL_MS = 200;
+ * Reduced from 200 to 50 — DOM.getDocument is ~2-6ms, so 50ms gives
+ * plenty of margin. Saves ~75ms avg per scrape (1.6-4.8s CF WASM init). */
+export const CHECKBOX_POLL_INTERVAL_MS = 50;
 
 /** Clean WS open timeout (ms). */
 export const CLEAN_WS_OPEN_TIMEOUT_MS = 2_000;

src/session/cf/cloudflare-solver.integration.test.ts

@@ -404,9 +404,9 @@ describe('CF Solver Integration (real nopecha.com)', () => {
       const polls = Number(checkboxFound!.payload.polls ?? 0);
       console.log(`  checkbox: found_at=${findMs}ms polls=${polls} method=${checkboxFound!.payload.method}`);
 
-      // MAX_CHECKBOX_POLLS = 16 in cf-schedules.ts — solver's actual polling budget.
+      // MAX_CHECKBOX_POLLS = 64 in cf-schedules.ts — solver's actual polling budget.
       // nopecha.com's Turnstile widget render time varies by CF's server-side timing.
-      expect(polls).toBeLessThanOrEqual(16);
+      expect(polls).toBeLessThanOrEqual(64);
       expect(findMs).toBeLessThan(10_000);
 
       // Verify poll interval via phase3_strategy markers
@@ -420,7 +420,7 @@ describe('CF Solver Integration (real nopecha.com)', () => {
         const sleepGap = gap - cdpMs;
         console.log(`  poll_gap: ${gap}ms (cdp=${cdpMs}ms, sleep≈${sleepGap}ms)`);
         // Isolate sleep interval from CDP call time.
-        // CHECKBOX_POLL_INTERVAL_MS = 200 + scheduling overhead ≈ < 500ms.
+        // CHECKBOX_POLL_INTERVAL_MS = 50 + scheduling overhead ≈ < 500ms.
         expect(sleepGap).toBeLessThan(500);
         // Full gap sanity: even with slow CDP under concurrent load, < 3s
         expect(gap).toBeLessThan(3000);