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

docs/porting-notes.md

@@ -0,0 +1,105 @@
+
+## 2026-11-11T11:42:59-03:00 staging
+```sh
+stage: headers + skeletons
+```
+
+## 2026-11-11T11:43:18-03:00 staging
+```sh
+stage: headers + skeletons
+```
+
+## 2026-11-11T11:51:34-03:00 staging
+```sh
+stage: headers + skeletons
+```
+
+## 2026-11-11T11:52:34-03:00 staging
+```sh
+stage: headers + skeletons
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf.c -> pfsrc/pf.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_ioctl.c -> pfsrc/pf_ioctl.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_norm.c -> pfsrc/pf_norm.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_if.c -> pfsrc/pf_if.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_lb.c -> pfsrc/pf_lb.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_ruleset.c -> pfsrc/pf_ruleset.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_table.c -> pfsrc/pf_table.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_osfp.c -> pfsrc/pf_osfp.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/pf_syncookies.c -> pfsrc/pf_syncookies.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/radix.c -> compat/radix.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/rtable.c -> compat/rtable.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c crypto/sha2.c -> compat/sha2.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/ifq.c -> pfsrc/ifq.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/hfsc.c -> pfsrc/hfsc.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/fq_codel.c -> pfsrc/fq_codel.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c net/if_pflog.c -> pfsrc/if_pflog.c.c (includes→pfk.h; struct renames; sa_len nulled)
+```
+
+## 2026-11-11T12:08:01-03:00 staging
+```sh
+port_c netinet/ip_divert.c -> pfsrc/ip_divert.c (includes→pfk.h; struct renames; sa_len nulled)
+```