fix(sock): make Ns_SockCork take non-const Ns_Sock*; correct mutating API and silence const warnings

 - Removed "const" from declaration of sock in prototyes and implementation.

Rationale: the function mutates socket state (setsockopt
TCP_CORK/UDP_CORK) and updates sockPtr->flags; taking a const pointer
was misleading and required unsafe const-drops. The change eliminates
-Wdiscarded-qualifiers / -Wcast-qual at call sites and aligns type
with side effects.

The change improves API clarity: mutators must take non-const,

Author: gustafn

include/ns.h

@@ -3059,7 +3059,7 @@ Ns_SockSendFileBufs(Ns_Sock *sock, const Ns_FileVec *bufs, int nbufs, unsigned i
     NS_GNUC_NONNULL(1) NS_GNUC_NONNULL(2);
 
 NS_EXTERN bool
-Ns_SockCork(const Ns_Sock *sock, bool cork)
+Ns_SockCork(Ns_Sock *sock, bool cork)
     NS_GNUC_NONNULL(1);
 
 /*

nsd/sockfile.c

@@ -227,7 +227,7 @@ Ns_SockSendFileBufs(Ns_Sock *sock, const Ns_FileVec *bufs, int nbufs, unsigned i
  *----------------------------------------------------------------------
  */
 bool
-Ns_SockCork(const Ns_Sock *sock, bool cork)
+Ns_SockCork(Ns_Sock *sock, bool cork)
 {
     bool success = NS_FALSE;
 #if defined(TCP_CORK) || defined(UDP_CORK)