Problem

Every time you run dagger functions, the engine calls the SDK's moduleTypes hook, which runs live codegen inside a container just to figure out what functions and types your module exposes. This is slow and unnecessary — the answer only changes when your source code changes.

Solution

Move typedef discovery out of runtime. During dagger generate, persist the module's type definitions as a checked-in artifact (dagger.moduletypes.json). At load time, read that file instead of running SDK codegen. Keep the live codegen path as a fallback for bootstrap and stale artifacts.

Design

This PR is a first step + handoff draft:

1. Simplify ModuleTypes() — reuse baseWithCodegen() instead of duplicating ~45 lines of container setup. Same behavior, less code.
2. Add regression tests for three behaviors we must preserve:
   • Fresh source edits are visible immediately in dagger functions
   • Compile errors in function bodies don't break function listing
   • User init() doesn't run during typedef loading
3. Two design docs describe the full plan:
   • save-load-object-state.md — a generic engine primitive for saving/loading stable object state as portable JSON
   • codegen-moduletypes.md — using that primitive to persist module typedefs, so dagger functions becomes a file read instead of a codegen run