Add request-based push and worker middleware pipelines

[viktorprogger]

Summary

• Introduce request-based Push middleware processing through PushRequest.
• Add a configurable Worker middleware pipeline with WorkerRequest, dispatcher, stack, factory, and final handler.
• Keep failure orchestration in Worker; WorkerFinalHandler only resolves handlers and runs the Consume pipeline.
• Preserve the existing void WorkerInterface::process() contract and the current public role interfaces.
• Keep the existing Debug decorators, proxies, collector, and tracked-service wiring unchanged so this PR is independently mergeable.

Validation

• PHPUnit: 281 tests, 520 assertions
• Psalm
• PHP-CS-Fixer
• Composer dependency analyser
• PHP syntax lint
• Composer validation
• DI resolution and Worker failure-boundary smoke checks

[codecov]

Codecov Report

❌ Patch coverage is 99.05660% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 94.82%. Comparing base (7c79c3b) to head (3111e45).

Files with missing lines	Patch %	Lines
src/Middleware/Worker/WorkerMiddlewareFactory.php	95.65%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #338      +/-   ##
============================================
+ Coverage     94.58%   94.82%   +0.24%     
- Complexity      373      404      +31     
============================================
  Files            59       65       +6     
  Lines           978     1062      +84     
============================================
+ Hits            925     1007      +82     
- Misses           53       55       +2     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.