fix(composer): support slashes in dist download version routes

[joenivl]

Summary

• Fix dist download route to support branch versions containing slashes (e.g. dev-feat/ZON-185967-add-db-storage)
• Add regex constraints for version and reference route parameters
• Add test case for branch version downloads with slashes

Problem

Composer dev branch versions like dev-feat/my-feature contain forward slashes. When used in the dist download URL, Laravel's router splits the version on /, breaking parameter matching and returning
a 404.

Solution

Added where constraints to the dist download route:

• version: [a-zA-Z0-9_./-]+ — allows slashes
• reference: [a-f0-9]+ — restricted to hex (git SHA), so Laravel can distinguish version from reference

Test plan

• Existing dist download tests still pass
• New test: downloads dist for branch version with slashes
• Manually verified with curl against local Pricore instance

[maartenbode]

Thanks for the contribution, Jeroen! Clean fix and nice test coverage. All tests pass. 👍