Track Remoboard cross-promotion attribution

[everettjf]

Outcome

• preserves Remoboard UTM attribution for the ScriptWidget landing session
• emits landing, App Store, GitHub, and tutorial events through the shared dataLayer/Plausible-compatible event layer
• documents the funnel and the App Store Connect campaign-token activation step

Validation

• node --check site/analytics.js
• git diff --check
• verified the local landing page and primary App Store destination

Privacy and compatibility

• stores only allow-listed campaign parameters for the browser session
• does not add cookies or a third-party analytics account