release v0.9.4: drift unblock, fragnesia range fix, infra docs

- Sync docs/CVE_METADATA.json + KEV_CROSSREF.md to match the
  hand-applied core/cve_metadata.c entries from v0.9.3. Nightly
  drift-check (red since 2026-05-25) now passes. Pintheft's CWE
  landed as CWE-787 from NVD (was NULL in the hand-applied entry).
- Fix fragnesia (CVE-2026-46300) range table. Per NVD: bug entered
  at 5.11 SKBFL_SHARED_FRAG, vulnerable through 5.15.207 / 6.1.173 /
  6.6.140 / 6.12.90 / 6.18.32 / 7.0.9, fixed at .208/.174/.141/
  .91/.33/.10. Prior table had one entry {7,0,9} — off-by-one and
  missing every other backport. Added predates-5.11 introduction gate
  + test row.
- Update tools/verify-vm/README.md to document the v0.9.x infra:
  mainline kernel pinning via kernel.ubuntu.com, per-module
  provisioner hooks, two-phase prep→reboot→verify with post-reboot
  kernel confirmation, GRUB_DEFAULT pinning.
- Add curl fallback for NVD lookups in refresh-cve-metadata.py.
  Mirrors the CISA path's existing fallback. Prevents the silent
  Python urlopen hang seen during v0.9.3 prep (55-min stuck on
  CLOSE_WAIT socket; 30s timeout never fired).

docs/KEV_CROSSREF.md

@@ -4,7 +4,7 @@ Which SKELETONKEY modules cover CVEs that CISA has observed exploited
 in the wild per the Known Exploited Vulnerabilities catalog.
 Refreshed via `tools/refresh-cve-metadata.py`.
 
-**10 of 26 modules cover KEV-listed CVEs.**
+**12 of 34 modules cover KEV-listed CVEs.**
 
 ## In KEV (prioritize patching)
 
@@ -19,7 +19,9 @@ Refreshed via `tools/refresh-cve-metadata.py`.
 | CVE-2024-1086 | 2024-05-30 | CWE-416 | `nf_tables_cve_2024_1086` |
 | CVE-2022-0185 | 2024-08-21 | CWE-190 | `fuse_legacy_cve_2022_0185` |
 | CVE-2023-0386 | 2025-06-17 | CWE-282 | `overlayfs_setuid_cve_2023_0386` |
+| CVE-2025-32463 | 2025-09-29 | CWE-829 | `sudo_chwoot_cve_2025_32463` |
 | CVE-2021-22555 | 2025-10-06 | CWE-787 | `netfilter_xtcompat_cve_2021_22555` |
+| CVE-2018-14634 | 2026-01-26 | CWE-190 | `mutagen_astronomy_cve_2018_14634` |
 
 ## Not in KEV
 
@@ -30,7 +32,9 @@ and are technically reachable. "Not in KEV" is not the same as
 | CVE | CWE | Module |
 | --- | --- | --- |
 | CVE-2017-7308 | CWE-681 | `af_packet_cve_2017_7308` |
+| CVE-2019-14287 | CWE-755 | `sudo_runas_neg1_cve_2019_14287` |
 | CVE-2020-14386 | CWE-250 | `af_packet2_cve_2020_14386` |
+| CVE-2020-29661 | CWE-416 | `tioscpgrp_cve_2020_29661` |
 | CVE-2021-33909 | CWE-190 | `sequoia_cve_2021_33909` |
 | CVE-2022-0492 | CWE-287 | `cgroup_release_agent_cve_2022_0492` |
 | CVE-2022-25636 | CWE-269 | `nft_fwd_dup_cve_2022_25636` |
@@ -42,6 +46,10 @@ and are technically reachable. "Not in KEV" is not the same as
 | CVE-2023-32233 | CWE-416 | `nft_set_uaf_cve_2023_32233` |
 | CVE-2023-3269 | CWE-416 | `stackrot_cve_2023_3269` |
 | CVE-2023-4622 | CWE-416 | `af_unix_gc_cve_2023_4622` |
+| CVE-2024-26581 | ? | `nft_pipapo_cve_2024_26581` |
+| CVE-2024-50264 | CWE-416 | `vsock_uaf_cve_2024_50264` |
+| CVE-2025-6019 | CWE-250 | `udisks_libblockdev_cve_2025_6019` |
 | CVE-2026-31635 | CWE-130 | `dirtydecrypt_cve_2026_31635` |
 | CVE-2026-41651 | CWE-367 | `pack2theroot_cve_2026_41651` |
-| CVE-2026-46300 | ? | `fragnesia_cve_2026_46300` |
+| CVE-2026-43494 | ? | `pintheft_cve_2026_43494` |
+| CVE-2026-46300 | CWE-787 | `fragnesia_cve_2026_46300` |