chore: clarify dependency requirement scopes

[sidmohan0]

Summary

Tracks DFPY-66.

This PR tightens the dependency surface so requirement files match how the SDK is actually installed:

• makes requirements.txt a minimal runtime/core install file instead of a mixed runtime/optional/test/docs grab bag
• adds scoped requirement files for test, docs, and benchmark tooling
• keeps setup.py extras as the package-install source of truth while adding explicit test, docs, and benchmark extras
• updates CI, release, benchmark, tox, justfile, README, and CONTRIBUTING installs to use the scoped files/extras
• raises lower bounds for recently patched optional/security-sensitive packages in package extras where appropriate

Validation

• .venv313/bin/python -m pytest tests/ -m "not slow" --ignore=tests/test_gliner_annotator.py --ignore=tests/test_image_service.py --ignore=tests/test_ocr_integration.py --ignore=tests/test_spark_integration.py --ignore=tests/test_text_service_integration.py
  • 489 passed, 10 skipped, 291 deselected, 19 xfailed
• .venv313/bin/python -m pytest --collect-only tests/benchmark_text_service.py::test_regex_performance
• .venv313/bin/python -m pip install --dry-run -e ".[test,cli]" -r requirements-test.txt
• .venv313/bin/python -m pip install --dry-run -r requirements-dev.txt
• .venv313/bin/python -m pip install --dry-run -r requirements-benchmark.txt
• .venv313/bin/python setup.py egg_info
• .venv313/bin/python -m black --check setup.py
• git diff --check

Note: setup.py egg_info still emits the existing setuptools license-classifier deprecation warning; this PR does not change licensing metadata.