Document AIE2P vector type constraints and elementwise transform pattern

Add three new sections to CLAUDE.md based on hardware testing findings:
- AIE2P Vector Type Constraints: complete type mapping table showing which
  ops require bf16 vs f32, discovered from mlir-air/primitives and verified
  on NPU2 hardware
- Elementwise Activation Function Transform Pattern: the proven 10-phase
  transform template for relu/sigmoid/silu/gelu/leaky_relu
- Failure modes table for type constraint violations

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

Author: erwei-xilinx