fix(ts-sdk): Add primaryKey() and index() to SumBuilderImpl and SumColumnBuilder

[Ludv1gL]

Summary

• Codegen unconditionally emits .primaryKey() on all primary key columns, including enum types
• SumBuilderImpl (used for all object-form enums via __t.enum("Name", { ... })) only implemented Defaultable and Nameable — not PrimaryKeyable or Indexable
• This causes a runtime TypeError: SC.primaryKey is not a function whenever an enum type is used as a primary key column

Fix

Add Indexable and PrimaryKeyable interfaces and their methods to:

• SumBuilderImpl (the base class for all enum type builders)
• SumColumnBuilder (the column builder returned by SumBuilderImpl methods)

This matches the existing pattern already present in SimpleSumBuilderImpl and SimpleSumColumnBuilder.

Why SumBuilderImpl and not just SimpleSumBuilderImpl?

Codegen always generates object-form enums:

export const PlatformModuleType = __t.enum("PlatformModuleType", {
  Standard: __t.unit,
  Control: __t.unit,
});

The runtime dispatch in type_builders.ts (line ~3656) routes object-form enums to SumBuilder (backed by SumBuilderImpl), never to SimpleSumBuilder. So SimpleSumBuilderImpl's existing primaryKey()/index() methods are effectively dead code for codegen output.

Test plan

• Verify enum types used as primary keys no longer throw TypeError: SC.primaryKey is not a function
• Verify existing SimpleSumBuilderImpl/SimpleSumColumnBuilder behavior is unchanged (subclass overrides still work)

🤖 Generated with Claude Code