feat: add human-like behavioral layer (humanize option)

Bezier mouse curves, per-character typing with mistype simulation,
smooth micro-step scrolling, idle micro-movements between actions.

Supports both sync and async Playwright APIs. Patches page, frame,
context, browser, and Locator class methods.

Two presets: 'default' (normal speed) and 'careful' (slower, deliberate).
Configurable via HumanConfig dataclass / interface with full override support.

Bug fixes (from PR review):
- fill()/clear(): platform-aware select-all (Meta+a on macOS, Control+a elsewhere)
- sync Locator check()/uncheck(): wrap mouse_move in RawMouse-compatible object
- resolve_config(): raise error on unknown preset name
- Lazy-load human.config via __getattr__ in __init__.py
- humanPreset typed as 'default' | 'careful' literal union
- browser.newPage() patches implicit context

Tests: Python 36/36, JS Vitest 34/34, visual Python 17/17, JS 13/13

js/src/human/scroll.ts

@@ -0,0 +1,150 @@
+/**
+ * cloakbrowser-human — Human-like scrolling via mouse wheel events.
+ */
+
+import type { Page } from 'playwright-core';
+import { HumanConfig, rand, randRange, randIntRange, sleep } from './config.js';
+import { RawMouse, humanMove } from './mouse.js';
+
+interface ElementBounds {
+  x: number;
+  y: number;
+  width: number;
+  height: number;
+}
+
+function isInViewport(
+  bounds: ElementBounds,
+  viewportHeight: number,
+  cfg: HumanConfig,
+): boolean {
+  const topEdge = bounds.y;
+  const bottomEdge = bounds.y + bounds.height;
+  const zoneTop = viewportHeight * cfg.scroll_target_zone[0];
+  const zoneBottom = viewportHeight * cfg.scroll_target_zone[1];
+  return topEdge >= zoneTop && bottomEdge <= zoneBottom;
+}
+
+async function smoothWheel(raw: RawMouse, delta: number, cfg: HumanConfig): Promise<void> {
+  const absD = Math.abs(delta);
+  const sign = delta > 0 ? 1 : -1;
+  let sent = 0;
+  while (sent < absD) {
+    const stepSize = rand(20, 40);
+    const chunk = Math.min(stepSize, absD - sent);
+    await raw.wheel(0, Math.round(chunk) * sign);
+    sent += chunk;
+    await sleep(rand(8, 20));
+  }
+}
+
+export async function scrollToElement(
+  page: Page,
+  raw: RawMouse,
+  selector: string,
+  cursorX: number,
+  cursorY: number,
+  cfg: HumanConfig,
+): Promise<{ box: ElementBounds; cursorX: number; cursorY: number }> {
+  const viewport = page.viewportSize();
+  if (!viewport) throw new Error('Viewport size not available');
+
+  let box = await getElementBox(page, selector);
+  if (!box) {
+    await sleep(200);
+    box = await getElementBox(page, selector);
+    if (!box) throw new Error(`Element not found: ${selector}`);
+  }
+
+  if (isInViewport(box, viewport.height, cfg)) {
+    return { box, cursorX, cursorY };
+  }
+
+  // Move cursor into scroll area
+  const scrollAreaX = Math.round(viewport.width * rand(0.3, 0.7));
+  const scrollAreaY = Math.round(viewport.height * rand(0.3, 0.7));
+  await humanMove(raw, cursorX, cursorY, scrollAreaX, scrollAreaY, cfg);
+  cursorX = scrollAreaX;
+  cursorY = scrollAreaY;
+  await sleep(randRange(cfg.scroll_pre_move_delay));
+
+  // Calculate scroll distance
+  const targetY = viewport.height * rand(cfg.scroll_target_zone[0], cfg.scroll_target_zone[1]);
+  const elementCenter = box.y + box.height / 2;
+  const distanceToScroll = elementCenter - targetY;
+
+  const direction = distanceToScroll > 0 ? 1 : -1;
+  const absDistance = Math.abs(distanceToScroll);
+  const avgDelta = (cfg.scroll_delta_base[0] + cfg.scroll_delta_base[1]) / 2;
+  const totalClicks = Math.max(3, Math.ceil(absDistance / avgDelta));
+  const accelSteps = randIntRange(cfg.scroll_accel_steps);
+  const decelSteps = randIntRange(cfg.scroll_decel_steps);
+
+  let scrolled = 0;
+
+  // Scroll loop: accelerate → cruise → decelerate
+  for (let i = 0; i < totalClicks; i++) {
+    let delta: number;
+    let pause: number;
+
+    if (i < accelSteps) {
+      delta = rand(80, 100);
+      pause = randRange(cfg.scroll_pause_slow);
+    } else if (i >= totalClicks - decelSteps) {
+      delta = rand(60, 90);
+      pause = randRange(cfg.scroll_pause_slow);
+    } else {
+      delta = randRange(cfg.scroll_delta_base);
+      pause = randRange(cfg.scroll_pause_fast);
+    }
+
+    delta *= 1 + (Math.random() - 0.5) * 2 * cfg.scroll_delta_variance;
+    delta = Math.round(delta) * direction;
+
+    await smoothWheel(raw, delta, cfg);
+    scrolled += Math.abs(delta);
+    await sleep(pause);
+
+    // Check visibility every 3 steps
+    if (i % 3 === 2 || i === totalClicks - 1) {
+      box = await getElementBox(page, selector);
+      if (box && isInViewport(box, viewport.height, cfg)) {
+        break;
+      }
+    }
+
+    if (scrolled >= absDistance * 1.1) break;
+  }
+
+  // Optional overshoot + correction
+  if (Math.random() < cfg.scroll_overshoot_chance) {
+    const overshootPx = Math.round(randRange(cfg.scroll_overshoot_px)) * direction;
+    await smoothWheel(raw, overshootPx, cfg);
+    await sleep(randRange(cfg.scroll_settle_delay));
+
+    const corrections = randIntRange([1, 2]);
+    for (let c = 0; c < corrections; c++) {
+      const corrDelta = Math.round(rand(40, 80)) * -direction;
+      await smoothWheel(raw, corrDelta, cfg);
+      await sleep(rand(100, 250));
+    }
+  }
+
+  // Settle
+  await sleep(randRange(cfg.scroll_settle_delay));
+
+  box = await getElementBox(page, selector);
+  if (!box) throw new Error(`Element lost after scrolling: ${selector}`);
+
+  return { box, cursorX, cursorY };
+}
+
+async function getElementBox(page: Page, selector: string): Promise<ElementBounds | null> {
+  const el = page.locator(selector).first();
+  try {
+    const box = await el.boundingBox({ timeout: 2000 });
+    return box;
+  } catch {
+    return null;
+  }
+}