Allow beta-typed Modrinth builds for EasyAuth (easyauth:beta)

EasyAuth publishes its 26.x builds as beta on Modrinth, and the itzg
resolver only accepts release-typed versions by default, so the mc
container failed to start. Pin easyauth:beta in the default mod list and
teach the panel's mod manager to compare entries by base slug so version
qualifiers don't break protected/duplicate checks.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/mods-and-modpacks.md

@@ -36,9 +36,13 @@ restart the server.
 Managed mods are pinned by *project slug*, not version, in `.env`:
 
 ```
-MODRINTH_PROJECTS=fabric-api,easyauth,spark,lithium,ferrite-core
+MODRINTH_PROJECTS=fabric-api,easyauth:beta,spark,lithium,ferrite-core
 ```
 
+A `:beta` (or `:alpha`) suffix widens which release types are accepted for that
+project — EasyAuth publishes its 26.x builds as beta on Modrinth, so it needs the
+suffix. Without one, only release-typed builds are considered.
+
 Every time the server container (re)starts, the itzg image resolves each slug to the
 **newest release compatible with your Minecraft version** and downloads it. So: