types(entities): Type entity filter query operators

[javascrifer]

Why

The SDK runtime already forwards entity filter queries by JSON-serializing the query object, and Base44 accepts richer filter syntax than the current TypeScript signature exposes. Today filter() is typed as Partial<T>, so valid filters such as these produce TypeScript errors:

• base44.entities.Tool.filter({ uuid: ["uuid-1", "uuid-2"] })
• base44.entities.Tool.filter({ uuid: { $in: ["uuid-1", "uuid-2"] } })
• base44.entities.Tool.filter({ description: null }) when generated types mark the field as string | undefined

This makes developers and coding agents think supported Base44 filtering features are unavailable, and pushes users toward casts or any even when the query is valid.

What changed

• Added EntityFilterQuery<T> for filter() queries.
• Supports proven/documented filter syntax: exact values, null, array shorthand, $eq, $ne, $gt, $gte, $lt, $lte, $in, $nin, $exists, $regex, $all, $size, field-level $not, and root $and/$or/$nor.
• Keeps typed entity field keys so typos are still caught.
• Added JSDoc examples so editor completions and generated docs expose the available syntax.
• No runtime behavior change.

Verification

• npm run build

[raywiis]

👍