feat: Add anonymous usage tracking

[Soner (shyim)]

Summary

Adds anonymous usage tracking via UDP (same approach as deployment-helper) to understand how the web installer is used.

Tracked events

All events are sent as UDP JSON payloads to udp.usage.shopware.io:9000 with a random per-session user ID.

Event	Tags	When
web_installer.visit	source (admin or direct), language, php_version, os	First page load per session
web_installer.install.started	shopware_version	User starts a fresh install
web_installer.install.completed	shopware_version	Composer install succeeds
web_installer.install.failed	shopware_version	Composer install fails
web_installer.update.started	shopware_version_from, shopware_version_to, is_flex_project	User starts an update
web_installer.update.completed	shopware_version_from, shopware_version_to	Composer update succeeds
web_installer.update.failed	shopware_version_from, shopware_version_to	Composer update fails

Referer normalization

On the initial visit, the HTTP Referer header is normalized:

• Path contains /admin → source is admin (triggered from Shopware admin)
• Otherwise → source is direct (user accessed the installer directly)

Opt-out

Tracking is disabled when the DO_NOT_TRACK environment variable is set. The tracking endpoint can be overridden via SHOPWARE_TRACKING_DOMAIN.

Changes

• Services/TrackingService.php — Lightweight UDP tracking service (fire-and-forget, non-blocking)
• Listener/TrackingListener.php — Request listener that generates a session-scoped tracking ID and fires the visit event once
• Controller/InstallController.php — Tracks install started/completed/failed
• Controller/UpdateController.php — Tracks update started/completed/failed
• Tests updated to pass the new TrackingService dependency

Test plan

• All 83 existing tests pass
• PHPStan reports no errors
• PHP CS Fixer reports no issues

🤖 Generated with Claude Code

[Michael Telgmann (mitelg)]

maybe enum for the event names?