[clue]

This changeset updates our recommended Dockerfile to install PHP extensions via PIE instead of PECL. PIE is the official successor to the now deprecated PECL (https://wiki.php.net/rfc/adopt_pie_deprecate_pecl), and the upcoming PHP 8.6 images no longer ship the pecl command at all (docker-library/php#1654), so this prepares for updating to PHP 8.6 once it is released.

PIE installs the same ev extension, now v1.2.4 from Packagist instead of v1.2.3 from PECL, and writes the same docker-php-ext-ev.ini file as before. Builds keep compiling in parallel stages as per #315 and take about a second longer, the resulting image is otherwise unchanged. Likewise, the documentation for higher file descriptor limits now recommends installing ext-ev, ext-event or ext-uv using PIE.

Builds on top of #315, #136, #273, #149 and https://github.com/clue-engineering/icalforcalendly/pull/238 (private)
Refs docker-library/php#1654

[Copilot]

🟢 Approval recommended

No active review issues were identified for the PIE migration in the deployment guidance and integration Dockerfile.

No open issues 🎉

What changed in this PR

Migrates the recommended Docker build and deployment guidance from PECL to PIE, preparing for PHP 8.6 images that no longer include PECL.

Changes:

• Adds PIE to the shared build stage and uses it to install ext-ev, preserving parallel extension build stages.
• Updates event-loop extension recommendations to link to Packagist packages.
• Keeps the integration Dockerfile aligned with the documented example.

File	Description
tests/​integration/​Dockerfile-production	Installs PIE and replaces the PECL command for ext-ev.
docs/​best-practices/​deployment.md	Updates the Docker example and extension installation guidance to PIE.

_{Review effort: Balanced}