Docs: Update testing guide to use wp-env workflow

[galatanovidiu]

Why

Issue #19 identified that the testing.md documentation was outdated and didn't reflect the current wp-env-based testing workflow introduced in PR #18. The documentation still referenced manual database setup and Composer commands that are no longer the recommended approach for running tests.

Additionally, the testing guide was not discoverable - it wasn't linked from the main documentation index (docs/README.md) or referenced from CONTRIBUTING.md, making it difficult for contributors to find.

What

Updated docs/guides/testing.md

• Replaced manual database/Composer setup instructions with wp-env commands
• Updated all test commands to use npm run test:php with argument passing via --
• Fixed coverage generation commands (npm run wp-env start -- --xdebug=coverage)
• Corrected fixture documentation (DummyObservabilityHandler uses record_event(), not increment()/timing())
• Added exact file paths for coverage reports (tests/_output/html/index.html)
• Enhanced "What's Tested" section with accurate test file locations and specific test scenarios
• Replaced "CI Recommendations" with "Continuous Integration" showing actual CI implementation (test matrix, PHP/WP versions)
• Improved troubleshooting with context for when/why to run composer dump-autoload

Made testing guide discoverable

• Added "Contributing" section to docs/README.md linking to both CONTRIBUTING.md and testing.md
• Updated CONTRIBUTING.md to link to comprehensive Testing Guide instead of duplicating instructions

Verified accuracy

• Tested all documented commands to ensure they work correctly
• Verified test coverage claims against actual test files
• Confirmed CI configuration details match .github/workflows/test.yml

Testing

All commands in the updated documentation have been tested and verified to work:

• ✅ npm run test:php (all 357 tests pass)
• ✅ npm run test:php -- --filter test_name
• ✅ npm run test:php -- tests/Unit/Handlers/ToolsHandlerCallTest.php
• ✅ npm run wp-env start -- --xdebug=coverage
• ✅ Coverage report generation

Closes #19

[Copilot]

Pull Request Overview

This PR updates the testing documentation to reflect the current wp-env-based workflow and improves discoverability of testing resources. The changes align the documentation with the actual implementation introduced in PR #18, replacing outdated manual setup instructions with the containerized approach.

Key changes:

• Replaced manual database/Composer testing workflow with wp-env commands
• Made testing guide discoverable through main documentation index and CONTRIBUTING.md
• Updated test coverage commands, fixture documentation, and CI/CD information to match actual implementation

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
docs/guides/testing.md	Complete rewrite replacing manual setup with wp-env workflow, updated commands, fixture docs, and CI details
docs/README.md	Added "Contributing" section linking to CONTRIBUTING.md and testing.md for better discoverability
CONTRIBUTING.md	Replaced duplicated testing instructions with link to comprehensive Testing Guide

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[JasonTheAdams]

Mostly good, @galatanovidiu! Just one section that I'm wondering about.

[github-actions]

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Co-authored-by: galatanovidiu <[email protected]>
Co-authored-by: JasonTheAdams <[email protected]>
Co-authored-by: justlevine <[email protected]>

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.94%. Comparing base (040625e) to head (9f2b091).
⚠️ Report is 25 commits behind head on trunk.

Additional details and impacted files

@@            Coverage Diff            @@
##              trunk      #67   +/-   ##
=========================================
  Coverage     68.94%   68.94%           
  Complexity      821      821           
=========================================
  Files            46       46           
  Lines          3037     3037           
=========================================
  Hits           2094     2094           
  Misses          943      943           

Flag	Coverage Δ
unit	68.94% <ø> (ø)

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