refactor(marketing-pages)!: delete marketing-pages demo feature

Veect retrofit (ADR-027): fourth slice of the demo-content removal.
Deletes packages/marketing-pages whole and prunes every composition
edge in one commit: core-api router mount + dep, core-cms
collection/global composition + dep + regenerated Payload types,
web-next bindAll (prod + dev-seed) + tests + about page + Tailwind
source + transpilePackages + dep, cms/core-cms payload config test
assertions, marketing-page e2e spec, tsconfig paths, fallow ignore
entry, anchor-guard + generator e2e feature lists, compliance
data-map + retention-policy regeneration, lockfile prune, and
feature-list doc entries (CLAUDE.md, AGENTS.md, glossary, app/feature
AGENTS.md).

Event teardown: marketing-pages was the sole consumer of
auth.user.signed-up (welcome-email handler + job). The handler, its
Payload tasks, and the bus subscription all lived inside the package's
own binders, so they die with it — no other package wires the
subscription. Auth's manifest `publishes` stays untouched: a publisher
with zero consumers is legal (pnpm conformance only fails on orphan
consumers, verified green). The app-level sign-up-welcome-email test
asserted the marketing-pages mailer stays empty without a bus; it is
deleted with the feature, and the now-unused test-only bind-state
helpers in web-next bind-production.ts go with it.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

apps/web-next/AGENTS.md

@@ -26,7 +26,7 @@ pnpm dev --filter @repo/web-next   # Next.js on port 3000
 | ----------------------- | ---------------------------------------------------------------------------------------- |
 | `src/app/layout.tsx`    | Root layout — wraps app with `<Providers>`                                               |
 | `src/app/providers.tsx` | Client component wrapper (add tRPC/React Query here after scaffolding `@repo/core-trpc`) |
-| `src/app/page.tsx`      | Home page — navigation + marketing content                                               |
+| `src/app/page.tsx`      | Home page                                                                                |
 | `e2e/`                  | Playwright end-to-end tests                                                              |
 
 ## tRPC Setup (optional)
@@ -104,7 +104,7 @@ Run: `pnpm test:e2e` starts the dev server and runs all `.spec.ts` files.
 
 ## Cross-References
 
-- **Feature packages:** `packages/{auth,marketing-pages,navigation}/`
+- **Feature packages:** `packages/{auth,navigation}/`
 - **tRPC composition:** `packages/core-api/AGENTS.md`
 - **tRPC client + provider (optional):** scaffold `@repo/core-trpc` first, then see `turbo/generators/templates/core-package/trpc/AGENTS.md.hbs`
 - **UI components (optional):** scaffold with `pnpm turbo gen core-package ui`, then see `turbo/generators/templates/core-package/ui/AGENTS.md.hbs`