fix: Remove _libs/** and libs/** from global exclude defaults

These are project-specific directories and should be configured per
project in .codegraph/config.json, not hardcoded globally. Delphi-
specific excludes (__history, __recovery, *.dcu) remain as global
defaults since they are analogous to __pycache__ for Python.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/types.ts

@@ -536,8 +536,6 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
     '**/node_modules/**',
     '**/vendor/**',
     '**/Pods/**',
-    '**/_libs/**',
-    '**/libs/**',
 
     // Generic build outputs
     '**/dist/**',