chore(core): remove orphan PageTabs + clean post-i18n doc drift

- delete core.pageTabs.component.{vue,test} (zero consumers since SurfaceTabBar)
- MIGRATIONS.md: remove dangling src/lib/plugins/i18n.js reference; add PageTabs drop note
- billing.static-content.js: fix 3 stale "fallback to i18n keys" comments

Closes audit P1 (2026-05-21).

Author: PierreBrisorgueil

MIGRATIONS.md

@@ -266,6 +266,14 @@ This migration is **opt-in per module** — coordinate with the maintainer of ea
 
 ---
 
+## Drop CorePageTabsComponent (2026-05-21)
+
+The `core.pageTabs.component.vue` introduced in PR #4183 was abandoned 2h after merge in favor of `SurfaceTabBar` (PR #4187). The component had zero consumers and is removed.
+
+**Downstream action:** if you propagated `core.pageTabs.component.{vue,test}` via `/update-stack`, delete both files. Use `SurfaceTabBar` for any tab layouts.
+
+---
+
 ## Legal module + cookie consent banner (2026-05-07)
 
 **Non-breaking for default consumers.** New `modules/legal/` ships:
@@ -285,7 +293,7 @@ Disabled by default. Enable in `modules/legal/config/legal.{env}.config.js` (or
 - MODIFIED: `src/modules/core/components/core.footer.component.vue` — auto-injects a "Legal" section when `legal.cookieConsent.enabled` or any `legal.pages.items[*].enabled` is true. Also fixes a pre-existing bug where the footer was hidden on hard-load (the `$route` watcher didn't fire on initial mount); a `created()` hook now initializes `enabled` from `$route.meta.footer`.
 - MODIFIED: `src/modules/app/app.vue` — global mount of `<legalCookieBanner />`.
 - MODIFIED: `src/modules/app/app.router.js` — concatenates legal routes (returns empty when `pages.enabled: false`).
-- MODIFIED: `src/lib/plugins/i18n.js` — imports `legalEn` / `legalFr`.
+- ~~MODIFIED: `src/lib/plugins/i18n.js` — imports `legalEn` / `legalFr`.~~ **Superseded:** `src/lib/plugins/i18n.js` was removed entirely in PR #4169 (i18n removal). Legal strings are now hardcoded in English directly in the legal components.
 
 ### Action for downstream projects
 

src/modules/billing/config/billing.static-content.js

@@ -163,7 +163,8 @@ export const packs = [
 ];
 
 /**
- * @desc FAQ section content. Title + subtitle are optional (fallback to i18n).
+ * @desc FAQ section content. Title + subtitle are optional (fallback to hardcoded English defaults:
+ * `'Frequently asked questions'` / `null` — no subtitle by default).
  * @type {{ title?: string, subtitle?: string, content: Array<{id: string, question: string, answer: string}> }}
  */
 export const faqs = {
@@ -190,8 +191,8 @@ export const faqs = {
 
 /**
  * @desc Configurable tab labels (used in 'both-tabs' mode).
- * Each field is optional — when omitted the view falls back to i18n keys
- * `billing.pricing.tabs.plans` / `billing.pricing.tabs.units`.
+ * Each field is optional — when omitted the view falls back to hardcoded English defaults
+ * (`'Plans'` / `'Units'`).
  * Downstream projects can override either or both labels per project.
  * @type {{ plans?: string, units?: string }}
  */
@@ -201,8 +202,8 @@ export const tabs = {
 };
 
 /**
- * @desc Page header copy. When `null`/absent, falls back to i18n keys
- * `billing.pricing.title` / `billing.pricing.subtitle`.
+ * @desc Page header copy. When `null`/absent, falls back to hardcoded English defaults
+ * (`'Pricing'` / `'Choose the plan that fits your needs.'`).
  * @type {{ title?: string|null, subtitle?: string|null }}
  */
 export const header = {