Add CurseForge client and server metadata

[TheMarstonConnell]

What changed

• Capture the CurseForge file IDs returned by both mc-publish steps.
• Validate CurseForge's live Minecraft, loader, Java, Client, and Server version names.
• Update both published loader files through CurseForge's supported file-update API with the complete compatibility metadata.

Why

mc-publish v3.3 does not expose CurseForge's per-file environment field. As a result, releases include their Minecraft version, loader, and Java version but omit the Client and Server environment tags.

The post-publish update preserves the existing compatibility tags while adding both environments. Invalid API names or file IDs fail the release visibly instead of silently publishing incomplete metadata.

Impact

Future tagged releases will mark both NeoForge and Fabric files as compatible with client and server environments on CurseForge. Modrinth and GitHub release behavior is unchanged.

Validation

• Parsed .github/workflows/publish.yml successfully as YAML.
• git diff --check passes.
• ShellCheck passes for the new Bash step.
• Simulated both loader payloads and verified Minecraft 26.2 resolves to CurseForge 26.2.0.