Tidy up code and docs for publish

[Copilot]

Prepare repository for package publication by removing personal artifacts, cleaning commented code, and adding a lighthearted README note.

Changes

• Removed personal artifact: bld/clean.cmd containing local Windows paths
• Cleaned project file: Removed 7 commented XML lines from bld.csproj (symbol packages, runtime identifiers, license file references)
• Fixed TODO comment: Removed obsolete TODO in StatsCommand.cs about non-existent delete option
• Updated .gitignore: Added clean.cmd and clean.sh patterns to exclude generated cleanup scripts
• Enhanced README: Added lighthearted callout box about tool's origin to improve documentation tone

> 💡 **Fun fact**: `bld` was born from the frustration of watching gigabytes 
> of build artifacts pile up faster than dependencies in a JavaScript project. 
> Because sometimes you need a tool that speaks fluent MSBuild and knows when 
> to take out the trash. 🗑️

Original prompt

tidy up the code and docs for publish. docs should have a lighthearted note

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