Bubble Plugin API
JavaScript SDK surface for building Bubble plugins. Plugin authors write server-side actions, client-side actions, and visual elements that receive `(properties, context)` and read/write data through `BubbleThing` and `BubbleList` wrappers. Plugin API v4 replaces Fibers with native Promises and adds first-class type checks (`isBubbleThing`, `isBubbleList`), id-based lookups (`getThingById`, `getThingsById`), and async iteration on `BubbleList`.