fix: render channel-aware scoop checkver

[eareimu]

Summary

• provide serialized, channel-aware Scoop checkver template data
• keep product templates free of hard-coded stable or preview URLs
• bump the publish-false release-tooling version to 0.2.0-beta.9

Release contract

• publish surface: Git tag only; this crate remains publish = false
• consumer: gmutils v0.8.0-beta.5
• planned tag: v0.2.0-beta.9
• tag summary: channel-aware Scoop checkver template data

Verification

• cargo fmt -- --check
• cargo test
• cargo clippy --all-targets --all-features -- -D warnings