Add CLI quality checks

[rtcoder]

Changes

• Add +--------------+--------+---------------------+
  | Check | Status | Details |
  +--------------+--------+---------------------+
  | PHP syntax | ok | 132 file(s) checked |
  | File hygiene | ok | 143 file(s) checked |
  +--------------+--------+---------------------+
  �[0;32mLint checks passed.�[0m for PHP syntax and file hygiene checks.
• Add +-----------------+--------+---------------------------+
  | Check | Status | Details |
  +-----------------+--------+---------------------------+
  | Composer config | ok | composer.json valid |
  | PHP syntax | ok | 132 file(s) checked |
  | File hygiene | ok | 143 file(s) checked |
  | Test suite | ok | composer test passed |
  | Route list | ok | ./shift route:list passed |
  +-----------------+--------+---------------------------+
  �[0;32mQuality checks passed.�[0m for Composer validation, lint checks, test suite execution, and route listing.
• Introduce reusable quality check classes for CLI commands and diagnostics.
• Reuse the shared PHP syntax and test checks in .
• Clean existing trailing whitespace so file hygiene checks pass.
• Add tests for quality command discovery, PHP syntax checks, file hygiene failures, and lint output.
• Document quality commands in README, docs/index.html, and REFACTORING.md.

Verification

• composer test
• ./shift lint
• ./shift qa
• Documentation anchor check for all in-page navigation links
• ./shift help lint
• ./shift help qa

Release

• Version label: v0.21.0