docs: update CLAUDE.md with all session learnings

Major updates reflecting this session's architectural changes:
- Pipeline: index → enrich → serve (read-only serving layer)
- Spring AI 2.0.0-M3 with @mcptool annotations
- 30 MCP tools (removed analyze_codebase)
- ServiceDetector with 30+ build systems
- Framework discriminator guards
- LayerClassifier path heuristics
- Dead code semantic edge filtering
- E2E testing strategy with Context7 ground truth
- Neo4j property round-trip conventions
- Generic detection principles (not example-specific)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: aksOps