perf: Add Delphi-specific exclude patterns to defaults

Add _libs/**, libs/**, __history/**, __recovery/**, and *.dcu to
default exclude list. Delphi projects store external dependencies
in _libs/ or libs/ (often as Git submodules) and these should not
be indexed — same as node_modules for JS projects.

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

src/types.ts

@@ -536,6 +536,8 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
     '**/node_modules/**',
     '**/vendor/**',
     '**/Pods/**',
+    '**/_libs/**',
+    '**/libs/**',
 
     // Generic build outputs
     '**/dist/**',
@@ -630,6 +632,11 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
     '**/Carthage/Build/**',
     '**/SourcePackages/**',
 
+    // Delphi/Pascal
+    '**/__history/**',
+    '**/__recovery/**',
+    '**/*.dcu',
+
     // PHP
     '**/.composer/**',
     '**/storage/framework/**',