Add EasyBuild package ecosystem support

[AgentGoose32]

Summary

• add an EasyBuild ecosystem adapter backed by the easybuilders/easybuild-easyconfigs repository
• maps supported package names from easyconfig paths
• maps package metadata, versions, source metadata, dependencies, registry/documentation URLs, and install commands
• seeds docs.easybuild.io as the default EasyBuild registry
• adds model coverage for package discovery, metadata, versions, dependencies, URLs, and install commands

Refs #659

Validation

• ruby -c app/models/ecosystem/easybuild.rb
• ruby -c db/seeds.rb
• ruby -c test/models/ecosystem/easybuild_test.rb
• git diff --check

Full Rails test execution is blocked locally because this repo lockfile requires Bundler 4.0.10 while the system Ruby/Bundler cannot satisfy it.