Enhance documentation and add scripts for composer.json.

[terabytesoftw]

Q	A
Is bugfix?	✔️
New feature?	❌
Breaks BC?	❌
Tests pass?	❌

[Copilot]

Pull request overview

Updates developer-facing documentation and tooling configuration to standardize local validation commands via Composer scripts, while refreshing project README presentation.

Changes:

• Add docs/guide/internals.md documenting Composer scripts for CS/static analysis/tests and link it from the guide index.
• Update composer.json scripts to cs, cs-fix, static, and tests.
• Configure PHPCS to scan src and tests via phpcs.xml.dist, and adjust CI linter workflow inputs accordingly; refresh README header/badges/links.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
phpcs.xml.dist	Adds explicit src/tests targets for PHPCS.
docs/guide/internals.md	New guide page describing validation scripts.
docs/guide/README.md	Adds navigation link to the new internals page.
composer.json	Replaces PHPCS scripts and adds scripts for phpstan/tests.
README.md	Updates header logo markup and replaces badges; adds project links sections.
.github/workflows/linter.yml	Removes explicit directories input (likely relying on PHPCS config).

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.54%. Comparing base (5be821e) to head (656392b).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #554   +/-   ##
=========================================
  Coverage     46.54%   46.54%           
  Complexity      506      506           
=========================================
  Files            44       44           
  Lines          1579     1579           
=========================================
  Hits            735      735           
  Misses          844      844           

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