[codex] Generate per-tile-op PTO micro examples

[zhoubot]

Summary

• add a dedicated generator for one .pto file per public tile op that already has a micro-backed implementation
• check in the generated tile-op corpus under ptodsl/lib/a5/generated/tile_ops
• add regression coverage that locks the generated files to the current micro-backed tile-op set

Why

The repo already had micro-backed A5 tile helpers, but it only emitted a small fixed example set. This change makes the tile-op coverage concrete by generating one .pto artifact per supported tile op so each file shows the micro instructions that build that tile op.

What changed

• added ptodsl/lib/a5/tile_op_kernels.py as the per-op builder table
• added scripts/generate_tile_op_pto.py to regenerate the tile-op corpus
• checked in generated .pto files under ptodsl/lib/a5/generated/tile_ops
• added TILE_OP_GENERATION_INDEX.md to record generated vs blocked/not-applicable tile ops
• added tests/regression/test_generated_tile_op_pto.py

Validation

• PYTHONPATH=/Users/zhoubot/github/.llvm-19.1.7/build-mlir-py312/tools/mlir/python_packages/mlir_core:/Users/zhoubot/github/pto-org/PTOAS/install-src312:/Users/zhoubot/github/pto-org/PTOAS/build-src312/python /Users/zhoubot/github/.venv-ptoas-src312/bin/python scripts/generate_tile_op_pto.py
• PYTHONPATH=/Users/zhoubot/github/.llvm-19.1.7/build-mlir-py312/tools/mlir/python_packages/mlir_core:/Users/zhoubot/github/pto-org/PTOAS/install-src312:/Users/zhoubot/github/pto-org/PTOAS/build-src312/python /Users/zhoubot/github/.venv-ptoas-src312/bin/python -m pytest -q tests/regression
• result: 61 passed in 2.10s