✨ refactor(http): finish accepted requests and headers before drain

[abmmhasan]

Summary

• Refactor native HTTP workers and protocol attachments to finish pending request admissions before initiating application drain ♻️
• Update HTTP/1.1, HTTP/2, and HTTP/3 connection handlers to track uncompleted initial exchanges and header blocks 🎨
• Add tests covering request recycling and incomplete headers during draining across HTTP versions ✅
• Update workflow configurations to support release tags and condition checks 👷
• Document graceful sequence and protocol draining behavior during application shutdown 📝

Change

Type

• Bug fix
• New feature
• Refactor
• Performance
• Security or reliability
• Documentation or examples
• Dependency, CI or tooling
• Other

Behavior and Compatibility

• No observable behavior changed
• Existing behavior was corrected
• New behavior was introduced
• Public API or documented behavior changed
• Backward compatibility may be affected
• PHP, extension, platform or dependency requirements changed

Validation

• composer ic:ci

Focused validation

• composer ic:test:syntax
• composer ic:test:code
• composer ic:test:lint
• composer ic:test:sniff
• composer ic:test:duplicates
• composer ic:test:probe
• composer ic:test:comments
• composer ic:test:architecture
• composer ic:test:static
• composer ic:test:security
• composer ic:test:refactor

Performance

• Relevant benchmarks were added or updated
• Results were compared against a relevant baseline
• composer ic:benchmark
• composer ic:bench:quick
• composer ic:bench:chart

Implementation Notes

Review Focus

Checklist

• The change is focused and excludes unrelated modifications.
• Tests cover new, corrected and regression-prone behavior.
• Public API and backward-compatibility implications were considered.
• Documentation, examples and type information were updated where required.
• Performance claims are supported by reproducible benchmarks.
• No credentials, secrets, personal data or sensitive debug output are included.
• I followed CONTRIBUTING.md and the engineering principles.