v0.3.1: --dump-offsets tool + NOTICE.md per module

The README has been claiming "each module credits the original CVE
reporter and PoC author in its NOTICE.md" since v0.1.0, but only
copy_fail_family actually shipped one. Fixed.

  modules/<name>/NOTICE.md (×19 new + 1 existing): per-module
    research credit covering CVE ID, discoverer, original advisory
    URL where public, upstream fix commit, IAMROOT's role.

  iamroot.c: new --dump-offsets subcommand. Resolves kernel offsets
    via the existing core/offsets.c four-source chain (env →
    /proc/kallsyms → /boot/System.map → embedded table), then emits
    a ready-to-paste C struct entry for kernel_table[]. Run once
    as root on a target kernel build; upstream via PR. Eliminates
    fabricating offsets — every shipped entry traces back to a
    `iamroot --dump-offsets` invocation on a real kernel.

  docs/OFFSETS.md: documents the --dump-offsets workflow.
  CVES.md: notes the NOTICE.md convention + offset dump tool.

  iamroot.c: bump IAMROOT_VERSION 0.3.0 → 0.3.1.

modules/nf_tables_cve_2024_1086/NOTICE.md

@@ -0,0 +1,27 @@
+# NOTICE — nf_tables (CVE-2024-1086)
+
+## Vulnerability
+
+**CVE-2024-1086** — `nft_verdict_init` double-free → cross-cache UAF
+→ arbitrary kernel R/W.
+
+## Research credit
+
+Discovered, exploited, and disclosed by **Notselwyn** (Pumpkin),
+January 2024.
+
+Original advisory + exploit: <https://pwning.tech/nftables/>
+GitHub: <https://github.com/Notselwyn/CVE-2024-1086>
+
+Upstream fix: mainline 6.8-rc1 (commit `f342de4e2f33`, Jan 2024).
+Stable backports throughout Q1 2024.
+
+## IAMROOT role
+
+This module fires the malformed-verdict trigger (NFT_GOTO + NFT_DROP
+in the same verdict) via a hand-rolled nfnetlink batch — no libmnl
+dependency. The msg_msg cross-cache groom into kmalloc-cg-96 is wired
+but the full pipapo R/W stage is opt-in via `--full-chain`, which
+forges a pipapo_elem with a value-pointer pointing at modprobe_path.
+Per-kernel offset assumptions are documented; the shared finisher's
+sentinel arbitrates real vs. apparent success.