Docs: move documentation to README

[ohmyfelix]

What changed

• Moved package documentation from .docs/README.md into the root README.md.
• Kept the Contributte badge/contact scaffold and added a concise package intro, versions table, contents, and usage/configuration sections.
• Removed the obsolete .docs/README.md wrapper source.

Why

Refs contributte/contributte#75

Testing

• git diff --check
• Targeted README scans for duplicate headings, stale local .docs links/images, and ToC anchors.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (master@55fee68). Learn more about missing BASE report.

Additional details and impacted files

@@            Coverage Diff             @@
##             master      #112   +/-   ##
==========================================
  Coverage          ?   100.00%           
==========================================
  Files             ?         2           
  Lines             ?        33           
  Branches          ?         0           
==========================================
  Hits              ?        33           
  Misses            ?         0           
  Partials          ?         0           

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