refactor: rename lib/ to core/ for clearer core-module separation

Rename the top-level lib/ directory to core/ so the project root
immediately communicates which code is core platform and which lives
in modules/. PHP namespaces (MintyPHP\*) are unchanged — only the
Composer PSR-4 path mapping moves from lib/ to core/.

Module-internal lib/ directories (modules/*/lib/) are untouched.

Updated across the full stack:
- composer.json PSR-4 mapping
- bootstrap entry points (web/index.php, bin/*, tests/bootstrap.php)
- tooling configs (phpstan.neon, phpunit.xml, php-cs-fixer)
- 26 architecture contract tests
- enforcement-policy, guard-catalog, quality-gates
- all documentation (CLAUDE.md, README, 25 docs/, .agents/skills/)
- bin/qa-extended.sh search paths
- .claude/settings.local.json permission paths

Workflow: .agents/runs/CORE-LIB-RENAME-001/ (Analyst → Planner →
Executor → Code Review (4 findings fixed) → Security Review →
Acceptance Test → Finalizer)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/reference-domain-glossar.md

@@ -15,8 +15,8 @@ Alle Kernbegriffe kurz und einheitlich verstehen.
 - `Policy` / `Ability`: zentrale Autorisierungsregel.
 - `Tenant-Scope`: Regel, ob Zugriff im Ziel-Tenant erlaubt ist.
 - `Action`: Request-Einstieg in `pages/**`.
-- `Service`: Fachlogik in `lib/Service/**`.
-- `Repository`: SQL und Mapping in `lib/Repository/**`.
+- `Service`: Fachlogik in `core/Service/**`.
+- `Repository`: SQL und Mapping in `core/Repository/**`.
 - `Factory`: erstellt/verdrahtet Service-Objekte (z. B. `UserServicesFactory`).
 - `Gateway`: schmale Schnittstelle/Fassade zu Domain-Funktionen oder Querschnitt (z. B. `PermissionGateway`).
 - `AppContainer`: zentrale Service-Registrierung und -Auflösung (`app(Foo::class)`).