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

packages/core-cms/AGENTS.md

@@ -16,7 +16,7 @@
 - **`@repo/<feature>/cms`** subpath exports only (to get collections/globals)
   - e.g., `import { articles } from "@repo/blog/cms"`
   - e.g., `import { users } from "@repo/auth/cms"`
-  - e.g., `import { pages, siteSettings } from "@repo/marketing-pages/cms"`
+  - e.g., `import { header } from "@repo/navigation/cms"`
 
 ## Must NOT import
 
@@ -29,10 +29,12 @@
 ## Public exports
 
 From `package.json`:
+
 - `.` — the Payload config (default export) + buildConfig re-export
 - `./generated-types` — Payload-generated TypeScript types
 
 Example usage:
+
 ```typescript
 import { buildConfig } from "@repo/core-cms";
 // or