refactor(blog)!: delete blog demo feature

Veect retrofit (ADR-027): the template's demo content is being removed
to make room for the Veect package map. This slice deletes
packages/blog whole and prunes every composition edge in one commit:
core-api router mount, core-cms collections + regenerated Payload
types, web-next bindAll entry / home page / blog route / Tailwind
sources, blog e2e spec, tsconfig paths, fallow ignore entry,
anchor-guard + generator e2e feature lists, compliance artifacts,
and feature-list doc entries (CLAUDE.md, AGENTS.md, glossary).

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

apps/web-next/src/styles/app.css

@@ -1,7 +1,6 @@
 @import "tailwindcss";
 @source "../../../../packages/core-ui/src";
 @source "../../../../packages/navigation/src";
-@source "../../../../packages/blog/src";
 @source "../../../../packages/marketing-pages/src";
 @source "../../../../packages/media/src";
 @source "../../../../packages/auth/src";