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>

core/Service/Access/AuthorizationPolicyContextTrait.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace MintyPHP\Service\Access;
+
+trait AuthorizationPolicyContextTrait
+{
+    protected function actorUserId(array $context): int
+    {
+        return (int) ($context['actor_user_id'] ?? 0);
+    }
+
+    protected function hasPermission(int $userId, string $permissionKey): bool
+    {
+        return $userId > 0 && $this->permissionService->userHas($userId, $permissionKey);
+    }
+
+    protected function capabilitiesFromDecision(AuthorizationDecision $decision): array
+    {
+        $capabilities = $decision->attribute('capabilities', []);
+        return is_array($capabilities) ? $capabilities : [];
+    }
+}