Fix TypeScript declaration export shape

[Pugsin]

Fixes #3.

Summary:

• Rewrites the declaration file to use the standard CommonJS export = pattern.
• Keeps Address, Group, and Item types under an AddressCompiler namespace.
• Includes the runtime compile(addresses, uniqueList?) signature.

Verification before fix:

src/addresscompiler.d.ts(7,4): error TS1036: Statements are not allowed in ambient contexts.
src/addresscompiler.d.ts(14,3): error TS1038: A 'declare' modifier cannot be used in an already ambient context.
src/addresscompiler.d.ts(18,3): error TS2309: An export assignment cannot be used in a module with other exported elements.

Verification after fix:

npx --yes --package typescript@5.9.3 tsc --noEmit src/addresscompiler.d.ts

Result: exits 0.