site: state the agent count as eighteen (FRE-997, count half)

FRE-359 verdict B dropped the agent count instead of correcting it: the page
said thirteen while `AgentSpec.all` held eighteen, and the /agents table listed
13 of those rows. The count is a fact, not a claim, so this states it and makes
the table match the registry again.

- Landing island bullet and the marquee chip say 18 agents.
- /agents: title/description/ogTitle/H1 at eighteen, and the five missing rows
  are on the page — Kimi, GitHub Copilot CLI, Crush, Cursor, Amp — with events
  and gating taken from hook/setup.go, hook/normalize.go,
  hook/normalize_hosts.go, Sources/NookCore/Agents/HookConfigInstaller.swift
  and plugins/amp/index.ts. All five are Observe (kimi/copilot PreToolUse and
  PermissionRequest fire before the host's own check; Crush documents one
  event; a silent Cursor permission hook blocks; Amp's plugin API has no
  permission-wait event).
- agents.test.ts asserts the roster as an equality with the 18-name registry
  in registry order again, plus the count, instead of a subset check.
- remote-claims.test.ts keeps every FRE-323 remote removal guard and the parked
  copy, and drops only the two completeness bans the corrected count
  contradicts ("every coding agent", "Supported agents") — the ban existed
  because the page claimed the set and listed 13 of 18.
- positioning.md: the coverage row is publishable at 18.

This is the count/roster half of FRE-997 only. The remote-SSH restore is held
by the Chief of Staff against FRE-346 §3 and is not in this commit: no remote
tile, breakdown, demo, chip, /agents remote paragraph or drafts deletion here.

Gate: `bun test src/routes/nook` 18 pass / 0 fail; `bun run build` succeeds.

src/components/nook/FeatureBreakdowns.tsx

@@ -851,7 +851,7 @@ export default function FeatureBreakdowns() {
         title="Your whole fleet, in one pixel strip"
         body="Every session, every agent, one square each. The pill never wraps, never grows — an arriving question flashes the fire and swaps the slot, then hands the notch back."
         bullets={[
-          "Claude Code, Codex, Gemini CLI, OpenCode, Pi, Muse, Cursor and more",
+          "18 agents: Claude Code, Codex, Gemini CLI, OpenCode, Pi, Muse, and more",
           "Custom agents: your own coding agent can wire itself in from the published contract",
           "Slot rankings — you choose which data earns the notch",
           "You don't need a notch — external displays get the same island, floating top-center"

src/components/nook/IslandExtras.tsx

@@ -722,7 +722,7 @@ function LayoutMock() {
 /* ── Marquee ─────────────────────────────────────────────────────── */
 
 const CHIPS_A = [
-  "Agents wired in",
+  "18 agents",
   "Custom agents",
   "Six chiptunes",
   "Focus-aware slots",