#1375 : refactor(proxy) Deprecate 'proxy' parameter in BrowserConfig and enhance proxy string parsing

- Updated ProxyConfig.from_string to support multiple proxy formats, including URLs with credentials.
- Deprecated the 'proxy' parameter in BrowserConfig, replacing it with 'proxy_config' for better flexibility.
- Added warnings for deprecated usage and clarified behavior when both parameters are provided.
- Updated documentation and tests to reflect changes in proxy configuration handling.

tests/proxy/test_proxy_deprecation.py

@@ -0,0 +1,42 @@
+import warnings
+
+import pytest
+
+from crawl4ai.async_configs import BrowserConfig, ProxyConfig
+
+
+def test_browser_config_proxy_string_emits_deprecation_and_autoconverts():
+    warnings.simplefilter("always", DeprecationWarning)
+
+    proxy_str = "23.95.150.145:6114:username:password"
+    with warnings.catch_warnings(record=True) as caught:
+        cfg = BrowserConfig(proxy=proxy_str, headless=True)
+
+    dep_warnings = [w for w in caught if issubclass(w.category, DeprecationWarning)]
+    assert dep_warnings, "Expected DeprecationWarning when using BrowserConfig(proxy=...)"
+
+    assert cfg.proxy is None, "cfg.proxy should be None after auto-conversion"
+    assert isinstance(cfg.proxy_config, ProxyConfig), "cfg.proxy_config should be ProxyConfig instance"
+    assert cfg.proxy_config.username == "username"
+    assert cfg.proxy_config.password == "password"
+    assert cfg.proxy_config.server.startswith("http://")
+    assert cfg.proxy_config.server.endswith(":6114")
+
+
+def test_browser_config_with_proxy_config_emits_no_deprecation():
+    warnings.simplefilter("always", DeprecationWarning)
+
+    with warnings.catch_warnings(record=True) as caught:
+        cfg = BrowserConfig(
+            headless=True,
+            proxy_config={
+                "server": "http://127.0.0.1:8080",
+                "username": "u",
+                "password": "p",
+            },
+        )
+
+    dep_warnings = [w for w in caught if issubclass(w.category, DeprecationWarning)]
+    assert not dep_warnings, "Did not expect DeprecationWarning when using proxy_config"
+    assert cfg.proxy is None
+    assert isinstance(cfg.proxy_config, ProxyConfig)