fix: detect configFiles in subdirectories with deep scan fallback

[vishalpatel1994]

What Changed

Added existsDeep() to lib.ts — a recursive directory scanner that serves as an automatic fallback when the root-level configFiles check misses.

Updated detectTechnologiesInDir() so that configFiles detection now:

1. Checks the project root first (fast, existing behaviour)
2. If missed, falls back to a deep scan up to 3 directory levels, skipping node_modules, .git, Pods, etc.

No changes to skills-map.ts entries or the public API — existing config just works.

Why This Change

configFiles detection previously called existsSync(join(dir, fileName)), which only checks the project root. This silently missed real-world Apple platform projects where Package.swift or Podfile live in a subdirectory:

Project type	File location	Before	After
CocoaPods iOS (repo root = parent folder)	ProjectName/Podfile	❌ not detected	✅ swiftui
React Native	ios/Podfile	❌ not detected	✅ swiftui
SPM sub-package	Packages/DesignSystem/Package.swift	❌ not detected	✅ swiftui
Standard SPM project	Package.swift (root)	✅ works	✅ works

Testing Done

• 343/343 tests pass (node --test 'tests/*.test.ts')
• 11 new tests added: existsDeep unit tests + SwiftUI deep-detection integration tests
• Verified against 2 real CocoaPods projects (SkillCare, Jumper) at all nesting depths

Path: /ProjectRoot              → Detected: [swiftui, ruby] ✅
Path: /ProjectRoot/ProjectName  → Detected: [swiftui, ruby] ✅
Path: /ProjectRoot/ProjectName/ProjectName (Podfile at root) → Detected: [swiftui, ruby] ✅

Type of Change

• fix: Bug fix (non-breaking — no API or config changes)

Security & Quality Checklist

• No secrets or API keys committed
• Follows the project's coding standards
• No sensitive data exposed in logs or output

Documentation

No documentation changes needed — this is an internal detection improvement with no public API changes.