🔨 replace Black with Ruff formatter

[Miyamura80]

Summary

• replace Black formatter usage with ruff format in tooling and docs
• remove Black dependency and refresh uv.lock
• fix JSON formatting prune expression in Makefile

Testing

• make fmt

[greptile-apps]

Greptile Overview

Greptile Summary

This PR successfully migrates the codebase from Black to Ruff formatter. The changes are comprehensive and well-executed:

• Removed Black dependency from pyproject.toml and uv.lock
• Updated Makefile to use ruff format instead of black, including removal of Black from install_tools target
• Fixed IGNORE_LINT_DIRS syntax from pipe-separated to space-separated format
• Corrected FIND_PRUNE expression for proper JSON file filtering in make fmt
• Updated all documentation (README.md, CLAUDE.md, manual_docs/branch_comparison.md, .cursor/rules/makefile-commands.md) to reflect the change
• Applied Ruff formatting to test files, showing different formatting preferences (multi-line assert messages)
• Applied formatting to docs JSON/TypeScript files

The migration is clean with no logical issues. Ruff's existing configuration in pyproject.toml (line-length = 88) matches Black's previous settings, ensuring formatting consistency.

Confidence Score: 5/5

• This PR is safe to merge with no issues
• The migration from Black to Ruff formatter is complete and thorough. All references to Black have been properly removed, documentation has been updated consistently across the codebase, and the Makefile changes are correct. The formatting changes to test files are purely cosmetic (Ruff's style for multi-line strings differs slightly from Black's). No logical bugs or breaking changes were introduced.
• No files require special attention

Important Files Changed

Filename	Overview
Makefile	replaced Black with Ruff formatter, fixed IGNORE_LINT_DIRS syntax and FIND_PRUNE expression
README.md	updated documentation and feature table to replace Black with Ruff
manual_docs/branch_comparison.md	updated feature table to replace Black formatter with Ruff formatter
pyproject.toml	removed Black dependency from project dependencies
uv.lock	removed Black dependency from lock file

[greptile-apps]

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

check that manual_docs/branch_comparison.md:28 is updated to reflect Ruff instead of Black formatter for consistency

| Black formatter | ✅ | ✅ | Opinionated code formatting |

Prompt To Fix With AI

This is a comment left during a code review.
Path: README.md
Line: 44:44

Comment:
check that `manual_docs/branch_comparison.md:28` is updated to reflect Ruff instead of Black formatter for consistency

```
| Black formatter | ✅ | ✅ | Opinionated code formatting |
```

How can I resolve this? If you propose a fix, please make it concise.