Add LiteRT-LM deploy and Colab CLI workflow

[tony51307]

Summary

• add LiteRT-LM local deploy CLI and document the .tflite/.litertlm workflow
• migrate Colab guidance from colab-mcp to google-colab-cli with named session commands
• clarify Phase 5 eval workflow so agents customize project-specific test cases before running batch and compare eval
• make LiteRT packages optional deploy checks instead of training blockers

Verification

• python3 -m py_compile scripts/setup_colab.py scripts/litertlm.py scripts/detect_env.py scripts/detect_system.py scripts/colab_training.py scripts/mlx_eval_template.py scripts/mlx_eval_vision_template.py
• python3 scripts/litertlm.py --help
• python3 scripts/litertlm.py deploy --help
• AST parse of scripts/*.py
• exercised LiteRT missing-tokenizer and existing-.litertlm deploy paths