fix: support TypeScript 7 and Bun for locale file transpilation

[shadoworion]

Problem

TypeScript 7 (the Go-based compiler, stable since typescript@7.0.x) no longer ships the JavaScript compiler API: ts.createProgram does not exist and the package's main entry only exposes version information. This breaks the generator with ts.createProgram is not a function.

Fixes #794

Solution

The generator now resolves a transpilation strategy for locale files at runtime:

1. Bun (process.versions.bun): locale files are bundled with the native Bun.build API — no typescript installation needed at all
2. TypeScript ≤ 6: the existing ts.createProgram path, unchanged, but behind a lazy import with feature detection (typeof ts.createProgram === 'function')
3. TypeScript 7: the installed package's tsc CLI is spawned (process.execPath + bin/tsc, no shell) with the same compiler flags; tsc emits even when it reports type errors (guaranteed because of --noLib), so the exit code is ignored and success is determined by the emitted files
4. Otherwise: a clear error message with instructions

The TypeScript version used for feature-gating the generated syntax (satisfies, template literal types, …) is detected lazily as well: versionMajorMinor → typescript/package.json version → a modern default. A missing or API-less typescript package therefore no longer crashes the CLI, importer or exporter at module-import time. typescript is now an optional peer dependency for Bun-only setups.

Also fixes a pre-existing bug: a missing await on containsFolders() in detectLocationOfCompiledBaseTranslation made its early-return dead code.

Verification

• TypeScript 5 regression (Node): full workspace test suite (412 tests) + tsc --noEmit + eslint pass; e2e run against a sample project (dictionary with JSON import) produces output identical to the published package
• TypeScript 7.0.2: version detected as 7.0.x, dictionary parsed via the spawned tsc CLI (all flags accepted by the native compiler), correct types generated
• No typescript installed (Node): graceful info log (assuming version >= 5.5) and an actionable error message
• Bun 1.3.14: generation works without typescript installed, watch mode regenerates types on dictionary changes, both TypeScript and JavaScript (module.exports) output formats work, JSON imports are bundled natively

🤖 Generated with Claude Code

[Sayrix]

I tested the Node fallback from this PR with TypeScript 7.0.2 in a project that has a tsconfig.json, and it still fails with:

error TS5112: tsconfig.json is present but will not be loaded if files are
specified on commandline. Use '--ignoreConfig' to skip this error.

The command exits with code 1 and emits no files. Adding --ignoreConfig to the tsc arguments fixes it and emits the expected JavaScript.

[Sayrix]

This also needs --ignoreConfig. With TypeScript 7.0.2, passing a source file while the project contains a tsconfig.json produces TS5112 and emits nothing. I confirmed that adding the flag makes the same command emit the expected files.

[shadoworion]

Good catch, thank you! Reproduced it — with a tsconfig.json present, tsc 7.0.2 aborts with TS5112 and emits nothing, so the fallback reported "No usable TypeScript compiler was found".

Fixed in 6f65ac0 by adding --ignoreConfig to the spawned arguments. The flag is passed unconditionally because this code path is only reachable on TypeScript >= 7 (older versions still provide the compiler API and take the programmatic ts.createProgram branch, which never read the user's tsconfig.json either — so behavior stays consistent).

Verified with TypeScript 7.0.2 + tsconfig.json (previously failing, now generates correctly) and re-ran the TypeScript 5 and Bun scenarios as regression.