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/deploy_joomla.php

@@ -31,7 +31,7 @@ require_once __DIR__ . '/../vendor/autoload.php';
 
 require_once __DIR__ . '/../lib/Enterprise/CliFramework.php';
 
-use MokoEnterprise\CliFramework;
+use MokoEnterprise\{CliFramework, SourceResolver};
 use phpseclib3\Net\SFTP;
 use phpseclib3\Crypt\PublicKeyLoader;
 
@@ -866,11 +866,11 @@ class DeployJoomla extends CliFramework
             }
         }
 
-        // 3-5. Fallback chain
-        foreach (['src', 'htdocs'] as $candidate) {
-            if (is_dir("{$repoPath}/{$candidate}")) {
-                return "{$repoPath}/{$candidate}";
-            }
+        // 3-5. Fallback chain (source/ → src/ → htdocs/)
+        $resolved = SourceResolver::resolveAbsolute($repoPath);
+        if ($resolved !== null) {
+            SourceResolver::warnIfLegacy($repoPath);
+            return $resolved;
         }
 
         // Last resort: repo root itself