chore: take vote-service out of the repository root

Removes the Go source, Dockerfile, go.mod, and Kubernetes manifests. The
deployed service is untouched and the review desk still calls it over
window.SKILLS_REVIEW_VOTE_API; only the source leaves.

The runbook does not leave. vote-service/README.md moves to
docs/vote-service.md, because it carries the parts that are hard to
rediscover: why the ingress overwrites X-Forwarded-For and Caddy stamps
X-Client-IP instead, why the image is side-loaded into containerd rather
than pulled, and why the PVC pins the Deployment to one node.

This drops verify.mjs from 84 assertions to 83. The removed one read
vote-service/main.go for X-Forwarded-For and 'one active vote per skill'
-- the review desk's only anti-abuse control -- and there is no file left
to read. It is the first assertion this repository has ever lost.

Rather than lower the gate's floor and leave a bare number behind,
gate.sh now subtracts the number of entries in
.agents/context/assertion-removals.md from the baseline. A removal costs
a written reason in a tracked file, in the same commit, as a visible
diff. Tested at 82 assertions: still refused.

Also drops the 22 MB of PNG baselines under .agents/snapshots/before/ and
before-reduced-motion/. They pictured the hand-written site, which no
longer exists; visual-regression.mjs has no compare mode to diff them
against; and they are recoverable from d88d8b8.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

AGENTS.md

@@ -18,8 +18,8 @@ labs are dependency-free HTML/CSS/JS that workshop attendees point an agent at.
   is the editorial CSS and the review-desk modules under `legacy/`, still
   imported by the pages that need them.
 - **Languages**: English and Brazilian Portuguese, toggled client-side
-- **Companion service**: `vote-service/` (Go + Kubernetes) — separate lifecycle,
-  see its own README
+- **Companion service**: a Go + Kubernetes vote API, reached over
+  `window.SKILLS_REVIEW_VOTE_API`. Its source is no longer in this repository
 
 ## Essential commands
 
@@ -54,7 +54,6 @@ it.
   ship as static assets.
 - `submitted-skills/` — other people's submitted work, reproduced verbatim
 - `skill-reviews/improved/` — generated; edit `src/content/reviews/*.md` instead
-- `vote-service/` — separate deploy lifecycle; do not fold into the site build
 - `dist/`, `node_modules/` — build output, never committed
 - `pnpm-lock.yaml` — **committed, but never hand-edited.** Change it only as a
   side effect of `pnpm install`. Every worktree spins up with