[codex] Production harden TEK core install and CI

[joy7758]

Summary

Production-hardens the TEK repository after the v0.1.0 release by splitting core and optional dependencies, adding deterministic runtime metadata, and introducing CI coverage for core runtime checks.

Changes

• Split dependency surfaces into requirements-core.txt, requirements-viz.txt, and requirements-dev.txt.
• Moved visualization libraries out of default install into .[viz] and .[dev] extras.
• Added explicit deterministic/stochastic CLI controls and runtime trace metadata.
• Added a frozen benchmark smoke profile with fixed seeds and step count.
• Added GitHub Actions CI for core install, unittest, CLI smoke, and frozen benchmark smoke.
• Updated README and agent_manifest.json with install, CI, benchmark, and reproducibility surfaces.

Validation

• git diff --check
• python3 -m json.tool agent_manifest.json
• python3 -m unittest discover -s tests
• python3 -m cli.main --steps 8 --seed 42 --deterministic --output artifacts/final-cli-smoke.json
• python3 -m benchmark.runner --smoke --output artifacts/final-benchmark-smoke.json
• python3 -m venv .venv-core && .venv-core/bin/python -m pip install -e . && .venv-core/bin/python -m cli.main --config configs/default.yaml --steps 3 --seed 42

Release note

This PR does not move the existing v0.1.0 tag or create a new release. After merge, v0.1.1 can be cut as a production-hardening patch release.