feat(core): add actions, guards, delays to SetupTypes interface

[cevr]

Summary

• Adds type slots for actions, guards, and delays to the SetupTypes interface
• Enables explicit type annotations for machines, helping break TypeScript inference chains
• Addresses performance issues and "excessively large and possibly infinite" type errors in large codebases

Problem

In large codebases that share types between backend and frontend, TypeScript's inference on actions/guards/delays can cause:

• Significant slowdowns in type checking
• "Excessively large and possibly infinite" TypeScript errors
• Inability to explicitly type machines like const machine: StateMachine<...> = setup({...}).createMachine({})

Solution

Add actions, guards, and delays to SetupTypes (like the existing context, events, etc.). This allows users to declare types explicitly rather than relying solely on inference.

// Before: Types always inferred from implementations, causing deep inference chains
const { createMachine } = setup({
  actions: {
    increment: assign(({ context }) => ({ count: context.count + 1 })),
  }
});

// After: SetupTypes includes action/guard/delay slots for explicit annotation support
type MySetupTypes = {
  context: { count: number };
  events: { type: 'INC' };
  actions: { type: 'increment'; params: undefined };
  guards: { type: 'isValid'; params: undefined };
  delays: 'timeout';
};

Changes

• types.ts: Add TAction, TGuard, TDelay type parameters and properties to SetupTypes
• setup.ts: Pass action/guard/delay types to SetupTypes in the types parameter
• setup.types.test.ts: Add tests for new type slots

Test plan

• TypeScript typecheck passes
• All 159 setup type tests pass
• All 1687 tests in the core package pass

🤖 Generated with Claude Code

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[davidkpiano]

cc. @Andarist to take a quick look to see if this is needed