fix: CurlCffi preserves duplicate Set-Cookie and get_cookies survives cross-domain names

CIMultiDict(response.headers) consumed curl_cffi Headers.items(), which comma-joins
duplicate header keys, collapsing multiple Set-Cookie lines into one corrupted value -
now uses multi_items() so duplicates stay separate. get_cookies used dict(cookies.items()),
which raises curl_cffi CookieConflict when the same name exists on two domains - now uses
get_dict() (flattens, no raise). Noble.get_cookies prefers get_dict() where the jar exposes
it (unverified live-gap: the noble extra isn't installed here).

Signed-off-by: disqualifier <dev@disqualifier.me>

src/aioweb_tls/backends.py

@@ -179,7 +179,7 @@ class CurlCffi:
         content = response.content if response.content is not None else b""
         return Response(
             status_code=response.status_code,
-            headers=CIMultiDict(response.headers),
+            headers=CIMultiDict(response.headers.multi_items()),
             content=content,
             url=str(response.url),
             reason=getattr(response, "reason", None),
@@ -208,8 +208,13 @@ class CurlCffi:
         session.cookies.set(name, value, domain=domain or "", path=path)
 
     def get_cookies(self, session) -> dict:
-        """all cookies stored in curl_cffi's cookie store"""
-        return dict(session.cookies.items())
+        """all cookies stored in curl_cffi's cookie store
+
+        uses get_dict() rather than dict(cookies.items()): items() raises curl_cffi
+        CookieConflict when the same name exists on two domains, get_dict() flattens
+        (last value wins) without raising.
+        """
+        return session.cookies.get_dict()
 
     def clear_cookies(self, session) -> None:
         """clear curl_cffi's cookie store"""
@@ -339,8 +344,15 @@ class Noble:
         session.cookies.set(name, value, domain=domain or "", path=path)
 
     def get_cookies(self, session) -> dict:
-        """all cookies stored in noble_tls's cookie jar"""
-        return dict(session.cookies.items())
+        """all cookies stored in noble_tls's cookie jar
+
+        prefers get_dict() when the jar exposes it (flattens cross-domain duplicate
+        names without raising, like curl_cffi); falls back to items() otherwise
+        """
+        jar = session.cookies
+        if hasattr(jar, "get_dict"):
+            return jar.get_dict()
+        return dict(jar.items())
 
     def clear_cookies(self, session) -> None:
         """clear noble_tls's cookie jar"""