* build: add chrome-release-verify and chrome-release-cls skills
Adds two project skills under .claude/skills/ for security backports:
* chrome-release-cls — given a Chrome Releases blog post URL, extract
every CVE/bug and locate the underlying Gerrit CL by searching the
local Chromium checkout and sub-repos.
* chrome-release-verify — end-to-end backport flow for a release
branch: maps CVEs→CLs, verifies which fixes are already in the synced
source tree, writes the cherry-pick patches locally, validates with
`e sync --3` + `lint --patches` (with the export→lint→re-apply loop),
then opens a single PR with the linked-CL/crbug/CVE body format.
* ci: skip platform builds for .claude/** changes
85be1a05e1