refactor(navigation)!: delete navigation demo feature

Veect retrofit (ADR-027): fifth and final slice of the demo-content
removal. Deletes packages/navigation whole and prunes every composition
edge in one commit: core-api router mount + dep + router test, core-cms
header-global composition + dep + regenerated Payload types (globals
now empty), web-next bindAll (prod + dev-seed) + tests + Tailwind
source + transpilePackages + dep, cms/core-cms payload config test
assertions, home e2e nav assertion, tsconfig paths, fallow
ignoreDependencies entry, anchor-guard FEATURES list, generator e2e
strip lists + reference-feature comments (navigation -> auth, incl.
feature templates + scaffolding guide), lockfile prune, and
feature-list doc trims (CLAUDE.md, AGENTS.md, glossary, app/feature
AGENTS.md). Compliance YAML regeneration produced no churn (navigation
declared no PII).

Cycle break: navigation's UI hooks were the last edge closing the
committed core-trpc -> core-api -> navigation -> core-trpc package
cycle. With it gone, the lint turbo task graph builds for the first
time and every package's ESLint executes; the epic's lint waiver
expires here. Latent findings: 3 errors, all mechanical, fixed
in-slice - require() import in turbo/generators/config.ts
(no-require-imports), literal type assertion in auth's
authentication.service.ts (prefer-as-const), and next-env.d.ts
triple-slash in apps/cms (rule scoped off for that generated file,
mirroring web-next's existing override). 99 warn-severity findings
remain across 5 packages (pii-declaration-must-be-complete on test
fixtures, turbo/no-undeclared-env-vars on test env keys) - all
warn-by-design, non-gating.

core-trpc keeps a consumer (apps/web-next providers) and stays per
ADR-027. Its unused @trpc/react-query dependency, surfaced by the
post-deletion fallow audit, is removed rather than ignore-listed -
core-trpc's hooks use @trpc/tanstack-react-query. Remaining fallow
warn (auth validateSession "unused member") is a false positive: the
method implements IAuthenticationService and is exercised in
container.test.ts; auth stays untouched as the regression canary.

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

docs/guides/scaffolding-a-feature.md

@@ -1,7 +1,7 @@
 # Scaffolding a feature
 
 `turbo gen feature` produces a feature package under
-`packages/<name>/` matching the shape of the reference `navigation` feature.
+`packages/<name>/` matching the shape of the reference `auth` feature.
 
 ## Invoking the generator
 
@@ -122,7 +122,7 @@ The realtime generators insert at three additional fixed `// <gen:realtime-*>` a
 
 - `CLAUDE.md` — Key Conventions (factory-style use cases, `.toDynamicValue()`,
   schemas-in-use-case, three binding modes per feature, span + capture sandwich)
-- `packages/navigation/AGENTS.md` — canonical reference shape the templates mirror
+- `packages/auth/AGENTS.md` — canonical reference shape the templates mirror
 - `docs/architecture/vertical-feature-spec.md` — design rationale for the layout
 - `docs/decisions/adr-012-feature-conventions.md` — file naming + factory pattern
 - `docs/decisions/adr-013-input-output-unification.md` — schemas-in-use-case + presenter