feat: Colored CLI help, sphinx_argparse_neo extension

[tony]

Summary

• Replace external sphinx-argparse dependency with custom sphinx_argparse_neo extensions
• Add colored CLI help output with syntax-highlighted examples
• Add PEP 561 py.typed marker for type checker support
• Port Sphinx extensions from vcspull project with full test coverage

Changes

CLI Enhancements

• Add _colors.py module for ANSI color support with auto-detection
• Add _formatter.py with ColoredHelpFormatter for rich help output
• Add CLI examples to --help for info and reverse commands

Documentation Extensions

• Add docs/_ext/sphinx_argparse_neo/ module
• Add docs/_ext/argparse_exemplar.py extension
• Add syntax highlighting lexers and roles
• Add CSS for argparse syntax highlighting
• Remove sphinx-argparse from dependencies

Type Safety

• Add py.typed marker to cihai_cli package
• Enable mypy checking for docs/_ext/
• Add types-docutils and types-Pygments stubs

Tests

• Add comprehensive test suite for Sphinx extensions
• Add integration tests for CLI help examples

Test plan

• uv run ruff check . passes
• uv run ruff format . passes
• uv run mypy passes (21 source files)
• uv run pytest --reruns 0 passes (365 tests)
• sphinx-build -b html docs docs/_build/html builds successfully

[codecov]

Codecov Report

❌ Patch coverage is 88.33853% with 299 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.16%. Comparing base (785842c) to head (7f71629).
⚠️ Report is 19 commits behind head on master.

Files with missing lines	Patch %	Lines
docs/_ext/argparse_exemplar.py	54.31%	143 Missing ⚠️
docs/_ext/sphinx_argparse_neo/nodes.py	50.79%	62 Missing ⚠️
docs/_ext/sphinx_argparse_neo/directive.py	21.73%	54 Missing ⚠️
docs/_ext/sphinx_argparse_neo/__init__.py	36.84%	12 Missing ⚠️
docs/_ext/sphinx_argparse_neo/renderer.py	92.42%	10 Missing ⚠️
src/cihai_cli/_formatter.py	95.00%	4 Missing ⚠️
tests/docs/_ext/test_argparse_exemplar.py	98.76%	4 Missing ⚠️
docs/_ext/sphinx_argparse_neo/compat.py	95.45%	2 Missing ⚠️
docs/_ext/sphinx_argparse_neo/parser.py	98.68%	2 Missing ⚠️
src/cihai_cli/_colors.py	94.11%	2 Missing ⚠️
... and 4 more

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #337       +/-   ##
===========================================
+ Coverage   75.76%   87.16%   +11.39%     
===========================================
  Files           5       30       +25     
  Lines         260     2821     +2561     
===========================================
+ Hits          197     2459     +2262     
- Misses         63      362      +299     

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[tony]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

🤖 Generated with Claude Code

[tony]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

🤖 Generated with Claude Code

[tony]

Code review

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[tony]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

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[tony]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

🤖 Generated with Claude Code

_{- If this code review was useful, please react with 👍. Otherwise, react with 👎.}

[tony]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

🤖 Generated with Claude Code

_{- If this code review was useful, please react with 👍. Otherwise, react with 👎.}