🚀 Sprint 11 Bouchée #1: Multi-File BIB Discovery with Smart Fallback

✨ ENHANCED: XmlBibConfigurationLoader with individual BIB file support
🎯 NEW CAPABILITY: Load from Configuration/bib_xyz.xml files
🛡️ COMPLETE ISOLATION: Each BIB in separate file = zero cross-contamination
🔄 SMART FALLBACK: Individual file first → Legacy XML fallback
📡 NEW METHOD: DiscoverAvailableBibIdsAsync() for BIB file discovery
🔒 BACKWARD COMPATIBLE: All Sprint 10 functionality preserved unchanged

🎯 CLIENT PROBLEM SOLVED:
   ❌ BEFORE: Single XML corruption stops ALL tests
   ✅ AFTER: Individual BIB files = complete operational isolation
   🚀 RESULT: Production tests continue uninterrupted

STRATEGY: LoadBibConfigurationAsync() now tries:
  1️⃣ Individual file (Configuration/bib_{bibId}.xml)
  2️⃣ Legacy XML system (existing Sprint 10 behavior)
  3️⃣ Intelligent caching for both approaches

🛡️ OPERATIONAL SAFETY: New BIB addition won't affect existing tests
⚡ ZERO RISK: Existing code continues working exactly as before
🏗️ FOUNDATION: Ready for Sprint 11 backup/rollback system

Sprint 11 Progress: 1/3 bouchées ✅ (Multi-File ✅, Backup ⏳, Validation ⏳)

Author: Eric Tremblayà