Add Script.declareVersion() and emit Versions type map in generated script contents

[Copilot]

Summary

Adds Script.declareVersion(coder, name) to register versioned type output by name/version and extends contents() to emit a Versions type alias representing that nested map. This enables version-aware type declarations to be generated alongside existing script exports.

• Version registry in Script

  • Added internal versions: Map<string, Map<string, ExportStatement>>.
  • Implemented declareVersion(coder, name) with duplicate protection per (name, version) key.

• Version declarations included in generation lifecycle

  • Extended isInProgress() / finished() to track version declaration promises.
  • Ensured contents() awaits completion before formatting.

• Versions type emission

  • Added versionsTypeStatements() and integrated it into contents() output.
  • Emits a type alias shaped as map-of-maps of versioned types.

script.declareVersion(new V1AccountTypeCoder({}), "Account");
script.declareVersion(new V2AccountTypeCoder({}), "Account");

// generated
export type Versions = {
  Account: {
    "1.0.0": { id: string };
    "2.0.0": { id: string; email: string };
  };
};

Original Prompt

Issue: script.declareVersion()

Add a new method to the Script class, declareVersion(coder, name).

It should work like export, adding some code to an internal Map called versions.

The key of the versions Map will be a string corresponding to the name. The value will be another Map with a key of version (taken from the coder) and value of the code generated by the coder.

The contents() method will declare a type named Versions whose value is the map of maps of types.

Manual acceptance tests

• Declaring two coders with the same name and different coder.version values emits both entries under that name in Versions.
• Calling contents() after declareVersion(...) includes an export type Versions = ... declaration in generated output.
• Re-declaring the same (name, version) pair does not create duplicate version entries.
• Existing import/export statement generation remains unchanged when no versions are declared.

Tasks

• Added versions state to Script and implemented declareVersion(coder, name).
• Wired version declaration promises into script completion tracking (isInProgress, finished).
• Added versionsTypeStatements() and injected Versions emission into contents().
• Added focused unit tests in test/typescript-generator/script.test.ts for version grouping and contents() output.