M1: compat layer + pf.ko skeleton builds against Linux 7.3.4

- pfk.h: BSD types/ioctl encoding (OpenBSD bit layout), locks (NET_LOCK=rwsem),
  pools, timeouts, mbuf shim over sk_buff, ifnet registry, toeplitz/siphash
- pfk_mod/pfk_hooks: misc /dev/pf (0600), IPv4 netfilter hook skeleton,
  DIOCGETSTATUS answered (M1 skeleton; engine ioctls land with pf_ioctl.c)
- vendorize/stage-port scripts: deterministic upstream staging with seds
  (struct renames, IFF_*->PFIFF_*, sa_len drops) logged to docs/porting-notes
- fixes: modules_prepare+Module.symvers for out-of-tree builds

module/include/compat/net/radix.h

@@ -0,0 +1,75 @@
+/* PFLINUX compat: <net/radix.h> — OpenBSD 8.0 radix structures/API
+ * (rn_*), cleaned of BSD-only syntax. Implementation: compat/radix.c
+ * (ported from OpenBSD 8.0 sys/net/radix.c, task T10). */
+#ifndef _PFK_RADIX_H
+#define _PFK_RADIX_H
+
+#include <linux/types.h>
+
+struct radix_mask;
+
+struct radix_node {
+	struct radix_mask	*rn_mklist;
+	struct radix_node	*rn_p;
+	short			rn_b;
+	char			rn_bmask;
+	u_char			rn_flags;
+#define RNF_NORMAL	1
+#define RNF_ROOT	2
+#define RNF_ACTIVE	4
+	union {
+		struct {
+			caddr_t		rn_Key;
+			caddr_t		rn_Mask;
+			struct radix_node *rn_Dupedkey;
+		} rn_leaf;
+		struct {
+			int		rn_Off;
+			struct radix_node *rn_L;
+			struct radix_node *rn_R;
+		} rn_node;
+	} rn_u;
+};
+
+#define rn_dupedkey rn_u.rn_leaf.rn_Dupedkey
+#define rn_key rn_u.rn_leaf.rn_Key
+#define rn_mask rn_u.rn_leaf.rn_Mask
+#define rn_off rn_u.rn_node.rn_Off
+#define rn_l rn_u.rn_node.rn_L
+#define rn_r rn_u.rn_node.rn_R
+
+struct radix_mask {
+	short			rm_b;
+	char			rm_unused;
+	u_char			rm_flags;
+	struct radix_mask	*rm_mklist;
+	union {
+		caddr_t		rmu_mask;
+		struct radix_node *rmu_leaf;
+	} rm_rmu;
+	int			rm_refs;
+};
+
+#define rm_mask rm_rmu.rmu_mask
+#define rm_leaf rm_rmu.rmu_leaf
+
+struct radix_node_head {
+	struct radix_node	*rnh_treetop;
+	int			rnh_addrsize;
+	int			rnh_pktsize;
+	struct radix_node	rnh_nodes[3];
+	u_int			rnh_rtableid;
+};
+
+void	rn_init(unsigned int);
+int	rn_inithead(void **, int);
+int	rn_walktree(struct radix_node_head *,
+	    int (*)(struct radix_node *, void *, u_int), void *);
+struct radix_node *rn_addroute(void *, void *, struct radix_node_head *,
+	    struct radix_node [2], u_int8_t);
+struct radix_node *rn_delete(void *, void *, struct radix_node_head *,
+	    struct radix_node *);
+struct radix_node *rn_lookup(void *, void *, struct radix_node_head *);
+struct radix_node *rn_match(void *, struct radix_node_head *);
+
+#endif /* _PFK_RADIX_H_ */