feat: support proxy dict with bypass field (#24)

The `proxy` parameter now accepts a Playwright proxy dict
({server, bypass, username, password}) in addition to URL strings.
Dict proxies are passed directly to Playwright, enabling bypass
lists and other advanced proxy options.

- Add ProxySettings TypedDict for Python type safety
- Extract server URL from dict proxies for geoip resolution
- Handle dict proxy args/auth in Puppeteer wrapper
- Strip inline credentials from dict proxy server URL in Puppeteer
- Fix JS launchContext() double-setting timezone (binary flag + context)
- Remove unnecessary non-null assertions in TS geoip helpers
- Use nullish coalescing for password fallbacks
- Add unit tests for geoip with dict proxy input

js/src/types.ts

@@ -5,8 +5,13 @@
 export interface LaunchOptions {
   /** Run in headless mode (default: true). */
   headless?: boolean;
-  /** Proxy server URL, e.g. 'http://proxy:8080' or 'socks5://proxy:1080'. */
-  proxy?: string;
+  /**
+   * Proxy server — URL string or Playwright proxy object.
+   * String: 'http://user:pass@proxy:8080' (credentials auto-extracted).
+   * Object: { server: "http://proxy:8080", bypass: ".google.com", ... }
+   *   — passed directly to Playwright.
+   */
+  proxy?: string | { server: string; bypass?: string; username?: string; password?: string };
   /** Additional Chromium CLI arguments. */
   args?: string[];
   /** Include default stealth fingerprint args (default: true). Set false to use custom --fingerprint flags. */