Add C vs Java MCP feature comparison; fix proprietary service name

New section "Feature Comparison: C vs Java MCP" documents:
- Feature parity on MCP essentials (initialize/tools/list/tools/call)
- Where C wins: startup (<100ms vs 1-3s), memory (30MB vs 512MB+),
  throughput (150K vs 73K MC sims/sec), Android/edge/IoT support
- Where Java wins: auto-schema from types, Spring Boot integration
- Design intent: static struct array is the C idiom for tool catalogs,
  not a limitation vs Java reflection

Also replaced proprietary service name in demo section.

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