feat(01-12): wave-6 task-1 — harness A18-A22 (font reachability + icon-distinct + manifest-i18n + Lora-resolved + welcome-tokens)

UAT harness extended with 5 new page-side assertions following the
01-13 Approach B pattern (page-side assertA* + host-side driveA*
wrapper + harness.test.ts orchestrator entry):

A18 — Lora WOFF2 reachable from harness page (font self-host MV3 CSP
  invariant). Walks document.styleSheets for the first @font-face rule
  referencing Lora, resolves the rebased asset URL (handles Vite's
  content-hashing), fetches, asserts byteLength >= 40_000 (subset Lora
  is ~49 KB) + WOFF2 signature 'wOF2'. 4 checks.

A19 — icons rasterized from Loom mark (not Bug A placeholders). Fetches
  icon128.png, parses IHDR bytes 24-25 (bit-depth + color-type),
  asserts (8, 6) RGBA vs the placeholder (16, 2) RGB. 2 checks.

A20 — manifest:name resolves via chrome i18n. Reads
  chrome.runtime.getManifest().name; asserts it matches EN extName
  'Mokosh — Session Capture' OR RU 'Mokosh — Запись сессии' (robust
  to whatever locale Chrome uses); explicitly checks no __MSG_
  placeholder leaks. 2 checks.

A21 — --mks-font-display resolves to Lora stack. Creates transient
  .mks-display-1 probe div, reads getComputedStyle.fontFamily,
  asserts the stack starts with 'Lora' or '"Lora"' (accommodates
  both quoted + unquoted forms across Chrome versions); explicitly
  checks no Newsreader leak (R2 substitution complete). 2 checks.

A22 — welcome page tokens.css adoption (CONDITIONAL on Plan 01-10).
  Skip-gate on missing welcome.html: catches both HTTP 404 AND
  network-layer fetch failure (Chrome extensions throw TypeError
  'Failed to fetch' for non-web_accessible_resources paths). On
  reachable: extracts <link rel=stylesheet> hrefs, fetches each,
  asserts >= 3 var(--mks-*) usages OR tokens.css reference. 1 check.

Companion changes:

- tests/uat/extension-page-harness.html gains `<link rel="stylesheet"
  href="../../src/shared/tokens.css">` so A18 + A21 have the @font-face
  rules + .mks-display-1 class + CSS custom properties resolvable via
  document.styleSheets + getComputedStyle. Vite's crxjs plugin handles
  the asset path rebasing at build:test time.

- tests/uat/lib/harness-page-driver.ts: driveA18..driveA22 wrappers
  following the established driveA8 pattern (page.evaluate → window.
  __mokoshHarness.assertXX). No new host-side fs/ffprobe primitives;
  all A18-A22 work is page-side.

- tests/uat/harness.test.ts: orchestrator drivers list extended with
  A18-A22 between A14 and A23. FORBIDDEN_HOOK_STRINGS UNCHANGED at 12
  entries post-Plan-01-14 (A18-A22 use production chrome.* + fetch +
  getComputedStyle exclusively; no new test-mode symbols).

Verification (this commit):
- npm run test:uat: 21/21 GREEN (was 16/16 post-01-14)
- SKIP_BUILD=1 npm test: 147/147 GREEN
- Tier-1 grep gate: 13/13 GREEN (no FORBIDDEN_HOOK_STRINGS growth)
- npx tsc --noEmit: clean
- npm run build + npm run build:test: both succeed

The chain of A1..A14 + A18..A22 + A23 runs in ~95 seconds end-to-end
under Puppeteer headless mode against the bundled Chrome at
~/.cache/puppeteer/chrome/linux-148.0.7778.167.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/uat/lib/harness-page-driver.ts

@@ -993,6 +993,105 @@ export async function driveA14(page: Page): Promise<AssertionRecord> {
   }) as AssertionRecord;
 }
 
+/* ─── Plan 01-12 Wave 6 — driveA18..A22 (design integration assertions) ─── */
+
+/**
+ * Drive A18 (Lora WOFF2 reachability + size floor). Standard
+ * page.evaluate wrapper — page side walks document.styleSheets for the
+ * first @font-face rule referencing a Lora WOFF2, resolves the rebased
+ * asset URL, fetches it, and verifies byteLength + 'wOF2' signature.
+ *
+ * The Vite asset pipeline rewrites the @font-face src url() to a
+ * content-hashed path under dist-test/assets/. Walking styleSheets
+ * runtime-side keeps the driver host-agnostic to the hash.
+ *
+ * @param page - The harness page from `launchHarnessBrowser`.
+ * @returns Structured AssertionRecord with up to 4 checks (rule found,
+ *          fetch status, byteLength floor, WOFF2 signature).
+ */
+export async function driveA18(page: Page): Promise<AssertionRecord> {
+  return await page.evaluate(async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- evaluate runs in browser context where Window types are loose.
+    const harness = (window as any).__mokoshHarness;
+    const r: AssertionRecord = await harness.assertA18();
+    return r;
+  }) as AssertionRecord;
+}
+
+/**
+ * Drive A19 (icons are NOT Bug A placeholders). Standard page.evaluate
+ * wrapper — page side fetches icon128.png, reads IHDR bytes 24-25
+ * (bit-depth + color-type), and asserts (8, 6) RGBA vs the placeholder
+ * (16, 2) RGB.
+ *
+ * @param page - The harness page from `launchHarnessBrowser`.
+ * @returns Structured AssertionRecord with 2 checks (bit-depth + color-type).
+ */
+export async function driveA19(page: Page): Promise<AssertionRecord> {
+  return await page.evaluate(async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- evaluate runs in browser context where Window types are loose.
+    const harness = (window as any).__mokoshHarness;
+    const r: AssertionRecord = await harness.assertA19();
+    return r;
+  }) as AssertionRecord;
+}
+
+/**
+ * Drive A20 (manifest:name resolves via chrome i18n). Standard
+ * page.evaluate wrapper — page side reads chrome.runtime.getManifest()
+ * and asserts manifest.name resolved to the EN or RU extName value
+ * (no __MSG_ placeholder leak).
+ *
+ * @param page - The harness page from `launchHarnessBrowser`.
+ * @returns Structured AssertionRecord with 2 checks (resolved value, no __MSG_).
+ */
+export async function driveA20(page: Page): Promise<AssertionRecord> {
+  return await page.evaluate(async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- evaluate runs in browser context where Window types are loose.
+    const harness = (window as any).__mokoshHarness;
+    const r: AssertionRecord = await harness.assertA20();
+    return r;
+  }) as AssertionRecord;
+}
+
+/**
+ * Drive A21 (--mks-font-display resolves to Lora). Standard
+ * page.evaluate wrapper — page side creates a transient .mks-display-1
+ * probe div, reads getComputedStyle.fontFamily, and asserts the stack
+ * starts with 'Lora' (no Newsreader leak).
+ *
+ * @param page - The harness page from `launchHarnessBrowser`.
+ * @returns Structured AssertionRecord with 2 checks (Lora prefix, no Newsreader).
+ */
+export async function driveA21(page: Page): Promise<AssertionRecord> {
+  return await page.evaluate(async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- evaluate runs in browser context where Window types are loose.
+    const harness = (window as any).__mokoshHarness;
+    const r: AssertionRecord = await harness.assertA21();
+    return r;
+  }) as AssertionRecord;
+}
+
+/**
+ * Drive A22 (welcome page tokens.css adoption — CONDITIONAL on Plan
+ * 01-10 having landed). Standard page.evaluate wrapper — page side
+ * fetches welcome.html; on HTTP 404 PASSES with a 'Plan 01-10 not
+ * landed; skipped' diagnostic. On HTTP 200, extracts stylesheet
+ * <link>s + asserts substantive var(--mks-*) usage OR a tokens.css
+ * reference in the linked CSS files.
+ *
+ * @param page - The harness page from `launchHarnessBrowser`.
+ * @returns Structured AssertionRecord with 1 check (skip or token usage).
+ */
+export async function driveA22(page: Page): Promise<AssertionRecord> {
+  return await page.evaluate(async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- evaluate runs in browser context where Window types are loose.
+    const harness = (window as any).__mokoshHarness;
+    const r: AssertionRecord = await harness.assertA22();
+    return r;
+  }) as AssertionRecord;
+}
+
 /* ─── Plan 01-14 — driveA23 (monitorTypeSurfaces picker-narrowing) ─── */
 
 /**