Prepare V1 release build, privacy, and backend hardening

[BrookenRecord]

Summary

• Move CI and release flows onto the Lute setup/build path, add backend test coverage in workflows, and add dry-run release artifact validation.
• Add Lute install/setup scripts, prod release preflight checks, and stricter package patch drift handling.
• Harden backend public endpoints with JSON body limits, rate-limit/payload errors, configurable GitHub redirects, and safer telemetry properties.
• Update plugin telemetry consent behavior to wait for saved consent, use per-install telemetry IDs, and redact/revoke Discord tokens.
• Refresh V1 release/privacy documentation and clean up web image loading states.

Testing

• CI workflows now run lute run lint, lute run analyze, lute run test, and backend cargo test.
• Release workflow dry run builds StudioActivity.rbxm and verifies prod build vars plus forbidden release-tree files.
• Added/updated backend WASM tests for error handling, redirects, and telemetry behavior.
• Not run locally from this PR content generation context.