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/Repository/Auth/RememberTokenRepositoryInterface.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace MintyPHP\Repository\Auth;
+
+/** Contract for remember-me token creation, rotation, expiry, and active session counting. */
+interface RememberTokenRepositoryInterface
+{
+    public function create(int $userId, string $selector, string $tokenHash, string $expiresAt): ?int;
+
+    public function findBySelector(string $selector): ?array;
+
+    public function updateToken(int $id, string $tokenHash, string $expiresAt): bool;
+
+    public function expireAllByAdmin(): int;
+
+    public function deleteById(int $id): bool;
+
+    public function deleteByUserId(int $userId): bool;
+
+    public function listByUserId(int $userId, int $limit = 20): array;
+
+    public function countActive(): int;
+}