Add gitty — single-binary Git/GitHub CLI to CLI tools section

[Omibranch]

gitty

gitty is a single-binary CLI tool written in Go that wraps Git and GitHub into short, human-readable commands.

Core idea: `gitty up` replaces the entire `git add → git commit → git push` cycle in one word.

Added right after Tig in the CLI tools section — both are git-related terminal tools.

Key features

• `gitty up` — stage, auto-commit, and push in one shot
• `gitty fix ` — interactive conflict resolution
• `gitty pick file.go 10-20` — selective line-range commits
• `gitty erase ` — remove from all past commits forever
• Written in Go — single binary, zero external dependencies
• Cross-platform: Linux, macOS, Windows