feat(core): add SourceResolver for backwards-compatible src/ → source/ migration

Introduces SourceResolver utility class with source/ → src/ → htdocs/
fallback chain, replacing hardcoded src/ references across 28 files.
This enables renaming root-level src/ to source/ in all repos while
maintaining backwards compatibility during the transition.

Phase 1: New lib/Enterprise/SourceResolver.php with resolve(),
resolveAbsolute(), globSource(), findUnderSource(), warnIfLegacy()
Phase 2: Updated 19 CLI/deploy tools to use SourceResolver
Phase 3: Updated 7 validator/lib files (McpServerPlugin,
PackageBuilder, RepositorySynchronizer, auto_detect_platform,
check_dolibarr_module, check_client_theme, check_structure)

Authored-by: Moko Consulting
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cli/release_create.php

@@ -17,7 +17,7 @@ declare(strict_types=1);
 
 require_once __DIR__ . '/../lib/Enterprise/CliFramework.php';
 
-use MokoEnterprise\CliFramework;
+use MokoEnterprise\{CliFramework, SourceResolver};
 
 class ReleaseCreateCli extends CliFramework
 {
@@ -97,8 +97,8 @@ class ReleaseCreateCli extends CliFramework
         // Find extension manifest (Joomla XML)
         $extManifest = null;
         $manifestFiles = array_merge(
-            glob("{$root}/src/pkg_*.xml") ?: [],
-            glob("{$root}/src/*.xml") ?: [],
+            SourceResolver::globSource($root, 'pkg_*.xml'),
+            SourceResolver::globSource($root, '*.xml'),
             glob("{$root}/*.xml") ?: []
         );
         foreach ($manifestFiles as $file) {
@@ -112,8 +112,7 @@ class ReleaseCreateCli extends CliFramework
         // Find Dolibarr module file
         $modFile = null;
         $modFiles = array_merge(
-            glob("{$root}/src/core/modules/mod*.class.php") ?: [],
-            glob("{$root}/htdocs/core/modules/mod*.class.php") ?: [],
+            SourceResolver::globSource($root, 'core/modules/mod*.class.php'),
             glob("{$root}/core/modules/mod*.class.php") ?: []
         );
         foreach ($modFiles as $file) {