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/fuse_legacy_cve_2022_0185/NOTICE.md

@@ -0,0 +1,32 @@
+# NOTICE — fuse_legacy (CVE-2022-0185)
+
+## Vulnerability
+
+**CVE-2022-0185** — `legacy_parse_param` in fsconfig() doesn't validate
+`PAGE_SIZE` against the running `fs_context`'s key/value length →
+4 KB heap OOB write → cross-cache UAF → cred overwrite from a
+rootless container.
+
+## Research credit
+
+Discovered and disclosed by **William Liu** + **Jamie Hill-Daniel**
+(Crusaders of Rust), January 2022.
+
+Original writeup: <https://www.willsroot.io/2022/01/cve-2022-0185.html>
+Public PoC: <https://github.com/Crusaders-of-Rust/CVE-2022-0185>
+
+Upstream fix: mainline 5.16.2 (Jan 2022).
+Branch backports: 5.16.2 / 5.15.14 / 5.10.91 / 5.4.171.
+
+## IAMROOT role
+
+userns+mountns reach, `fsopen("cgroup2")` + double
+`fsconfig(FSCONFIG_SET_STRING, "source", ...)` fires the 4k OOB,
+msg_msg cross-cache groom in kmalloc-4k. MSG_COPY read-back detects
+whether the OOB landed in an adjacent neighbour — the sanity gate
+that prevents fake-success claims.
+
+`--full-chain` extends with forged m_list/m_ts overflow toward
+modprobe_path via the shared finisher.
+
+**Container-escape angle** — relevant to rootless docker/podman/snap.