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/cgroup_release_agent_cve_2022_0492/NOTICE.md

@@ -0,0 +1,29 @@
+# NOTICE — cgroup_release_agent (CVE-2022-0492)
+
+## Vulnerability
+
+**CVE-2022-0492** — cgroup v1 `release_agent` privilege check in the
+wrong namespace → host root from a rootless container or unprivileged
+userns by mounting cgroup v1 and writing to `release_agent`.
+
+## Research credit
+
+Discovered by **Yiqi Sun** + **Kevin Wang** (Trend Micro Research),
+January 2022.
+
+Original writeup:
+<https://blog.trendmicro.com/cve-2022-0492-from-cgroup-loophole-to-container-breakout/>
+
+Upstream fix: mainline 5.17 (commit `24f6008564183`, March 2022).
+
+## IAMROOT role
+
+**Universal structural exploit — no per-kernel offsets, no race.**
+unshare(USER | MOUNT | CGROUP), mount cgroup v1 RDP controller,
+write `release_agent` → `./payload`, trigger via
+`notify_on_release` + cgroup process exit.
+
+Kept in the corpus as a portable "containers misconfigured"
+demonstration — works across every kernel below the fix without any
+tuning. Ships auditd rules covering cgroupfs mounts and
+`release_agent` writes.