Chore: Fix dev env friction, bump PHP floor to 8.3, add PHP matrix

[loks0n]

Summary

Cleanup after setting up the dev environment from scratch. Three themes:

Local dev parity with CI

• Dockerfile.fpm / Dockerfile.swoole now include composer, composer.json, composer.lock, phpstan.neon, and pint.json, so docker compose exec fpm composer {test,analyze,format:check} all work. Previously pint ran with the Laravel default preset in-container (pint.json wasn't copied), reporting 27 false-positive style issues that CI didn't see.
• CONTRIBUTING.md: fixed wrong service name (web → fpm), dropped stale psalm line (it's not a dep), documented the host-native inner loop (composer install && composer test) and the adapter-container e2e path for both FPM and Swoole.

PHP version policy

• Dropped PHP 8.2 support. require.php and the config.platform.php pin are now >=8.3 / 8.3. Dockerfile.fpm bumped to php:8.3-fpm-alpine. README and Getting-Started guide updated.
• CI unit job is now a matrix over 8.3 / 8.4 / 8.5 with per-version composer cache keys and fail-fast: false.
• Coverage (pcov + clover artifact) collected on the 8.3 leg only — floor version is the canonical coverage target.
• analyze job bumped to 8.3 too.

Misc

• example/docker-compose.yml: dropped deprecated version: '3'.

Left for a follow-up (discussed but out of scope here): moving the format job off docker-in-docker and onto setup-php, and making swoole e2e run natively on the runner (needs small source changes to parameterize port + base URL).

Test plan

Verified locally inside the rebuilt fpm container (PHP 8.3.30):

• composer test — 101 tests, 295 assertions, all green
• composer analyze — PHPStan no errors
• composer format:check — PER preset, 31 files pass
• e2e-fpm + e2e-swoole suites pass via docker compose exec
• CI matrix (8.3 / 8.4 / 8.5) — will run on this PR

🤖 Generated with Claude Code

[github-actions]

k6 benchmark

Throughput	Requests	Fail rate	p50	p95
8030 req/s	562127	0%	4.67 ms	12.09 ms

[greptile-apps]

Greptile Summary

This PR cleans up dev-environment friction by fixing Dockerfile parity with CI (adding composer, config files), correcting the CONTRIBUTING.md instructions, bumping the PHP floor to 8.3 consistently across all configuration files, and adding a PHP 8.3/8.4/8.5 matrix to the unit job with pcov coverage collected on the 8.3 leg only. One minor inconsistency: the composer.lock plugin-api-version regressed from 2.9.0 to 2.6.0, suggesting the lock file was regenerated with an older Composer than the composer:2.7 pinned in the Dockerfiles.

Confidence Score: 5/5

Safe to merge; all remaining findings are P2 style/consistency observations that don't block CI or correctness.

PHP version bumps are consistent across composer.json, composer.lock, Dockerfiles, CI, and docs. The CI matrix, coverage collection, and cache-key changes are all correct. The only finding is a lock-file plugin-api-version mismatch (P2), which will not break builds.

composer.lock — minor Composer version inconsistency worth cleaning up before the next lock-file churn.

Important Files Changed

Filename	Overview
.github/workflows/ci.yml	PHP matrix (8.3/8.4/8.5) added for unit job, per-version cache keys, coverage on 8.3 only; minor issue with always() usage on upload step and plugin-api-version downgrade in lock file
composer.json	PHP floor bumped from >=8.2 to >=8.3 in both require.php and config.platform.php; consistent change
composer.lock	Platform PHP updated to >=8.3/8.3; plugin-api-version downgraded from 2.9.0 to 2.6.0 and empty maps changed from {} to [], suggesting an older Composer version was used to regenerate the lock file
Dockerfile.fpm	Base image bumped to php:8.3-fpm-alpine; Composer 2.7 binary added; composer.json, composer.lock, phpstan.neon, pint.json copied for in-container script execution
Dockerfile.swoole	Composer 2.7 binary added; composer.json, composer.lock, phpstan.neon, pint.json copied for in-container script execution; mirrors fpm changes
CONTRIBUTING.md	Replaced stale docker exec instructions (wrong service name web, removed psalm); added host-native inner loop and container e2e paths
README.md	System requirements updated from PHP 8.2 to 8.3
example/docker-compose.yml	Removed deprecated version: '3' top-level key
docs/Getting-Starting-Guide.md	PHP requirement note updated from 8.2 to 8.3

_{Reviews (1): Last reviewed commit: "Chore: Regenerate composer.lock for PHP ..." | Re-trigger Greptile}

[greptile-apps]

Composer version mismatch in lock file

The plugin-api-version regressed from 2.9.0 to 2.6.0, and the empty stability-flags/platform-dev entries changed from JSON objects ({}) to arrays ([]). This means the lock file was regenerated with Composer ≈2.6.x on the host, while both Dockerfiles pin COPY --from=composer:2.7. When Composer 2.7 (in the container or CI) reads this lock file it may emit a "lock file is out of date" warning or silently re-normalise the file, causing spurious diffs for other contributors. Regenerating the lock file with composer:2.7 (or whichever version you want to treat as canonical) would keep the file consistent.