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/Console/Commands/Module/BuildCommand.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace MintyPHP\Console\Commands\Module;
+
+final class BuildCommand extends AbstractModuleCommand
+{
+    public function name(): string
+    {
+        return 'module:build';
+    }
+
+    public function description(): string
+    {
+        return 'Build runtime page root with module symlinks';
+    }
+
+    public function execute(array $args, array $options): int
+    {
+        $result = $this->moduleRunner()->build();
+        if ($result['status'] === 'ok') {
+            fwrite(STDOUT, sprintf(
+                "module-build: runtime pages built - %d core entries + %d module entries.\n",
+                $result['core_entries'],
+                $result['module_entries']
+            ));
+        } else {
+            fwrite(STDERR, $result['message'] . PHP_EOL);
+        }
+
+        if ($result['message'] !== 'module-build: ok' && $result['status'] === 'ok') {
+            fwrite(STDOUT, $result['message'] . PHP_EOL);
+        }
+
+        return (int) $result['exit_code'];
+    }
+}