Move PearcordPlatform to platform-pearcord-platform-class.js; add
platform-index-bindings.js to unpack preamble exports (including
id/now/guildTopic). index.js is now a thin finalize entry (7 lines).
Registries for bindings, class, and entry line limits. No behavior change.
Co-authored-by: Cursor <[email protected]>
