docs: Modernize README with comprehensive documentation

[jeremiahjordanisaacson]

Summary

• Add centered logo, badges (tests, release, license, Python version)
• Add navigation links to documentation site
• Add "Why Tally?" section explaining the value proposition
• Expand command reference table with all available commands
• Add step-by-step "How It Works" guide with configuration examples
• Document complete rule syntax (match functions, conditions, tag-only rules, field transforms)
• Add special tags reference (income, transfer, investment, refund)
• Add views/custom report sections documentation
• Document all output formats (HTML, JSON, CSV, Markdown)
• Add configuration reference with settings.yaml examples
• Add amount modifiers reference table
• Add tips & best practices section
• Add project structure diagram
• Add contributing section

Test plan

• Verify all markdown renders correctly on GitHub
• Verify badge URLs point to correct workflows/releases
• Verify documentation links work

🤖 Generated with Claude Code

[github-actions]

PR Build Available

Version: 0.0.83-d9f094a

Install from this PR

Linux / macOS:

curl -fsSL https://raw.githubusercontent.com/davidfowl/tally/main/docs/install-pr.sh | bash -s -- 83

Windows PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/davidfowl/tally/main/docs/install-pr.ps1) } 83"

Manual download: View workflow run and download artifacts.

Requirements

• GitHub CLI (gh) must be installed and authenticated
• Run gh auth login if not already authenticated