feat(security): default follow_redirects to "safe" for SSRF protection

curl_cffi v0.15.0 introduced CurlFollow.SAFE, which follows redirects but rejects those targeting internal/private IPs (loopback, private networks, link-local). This is now the default for all HTTP fetchers, the MCP server, and the shell curl converter.

Added FollowRedirects type alias supporting all curl_cffi redirect
modes: bool, "safe", "all", "obeycode", "firstonly".

scrapling/engines/_browsers/_types.py

@@ -19,6 +19,7 @@ from scrapling.core._types import (
     TypeAlias,
     SetCookieParam,
     SelectorWaitStates,
+    FollowRedirects,
 )
 from scrapling.engines.toolbelt.proxy_rotation import ProxyRotator
 
@@ -39,7 +40,7 @@ class RequestsSession(TypedDict, total=False):
     headers: Optional[Mapping[str, Optional[str]]]
     retries: Optional[int]
     retry_delay: Optional[int]
-    follow_redirects: Optional[bool]
+    follow_redirects: Optional[FollowRedirects]
     max_redirects: Optional[int]
     verify: Optional[bool]
     cert: Optional[str | Tuple[str, str]]