fix(extract): reject invalid CLI arguments

[oleksii-tumanov]

Summary

• parse and validate graphify extract arguments from one declarative option schema
• reject unknown options, missing values, unsupported empty/assignment forms, and extra positional arguments with exit code 2 before path or output work
• enforce the documented 0–100 --exclude-hubs range during parsing instead of returning a conversion traceback
• preserve supported spaced/inline forms, repeated-option semantics, and intentional empty PostgreSQL DSNs while omitting unknown option values from error output

Result

$ graphify extract . --unknown=value
error: unknown extract option: --unknown

Tests

• python -m pytest tests/ -q --tb=short — 3511 passed, 33 skipped
• python -m pytest tests/test_extract_cli_args.py tests/test_extract_cli.py -q --tb=short — 116 passed
• python -m ruff check graphify/cli.py tests/test_extract_cli_args.py
• all five tools.skillgen checks
• graphify update .

Closes #2025.

Related to #2004.