feat: add cdb-converter CLI

[mpicciolli]

Summary

Adds an installable cdb-converter command so files can be converted without writing any code — fulfilling the most visible gap (the repo only shipped sample scripts before).

The conversion direction is auto-detected from the input file extension:

Input extension	Direction	Default output
.cdb	CDB → SQLite	<input>.sqlite
.sqlite / .db	SQLite → CDB	<input>.cdb

npx cdb-converter save.cdb              # → save.sqlite
npx cdb-converter save.sqlite           # → save.cdb
npx cdb-converter save.cdb out.sqlite   # explicit output
npx cdb-converter --help | --version

Changes

• src/cli.ts — the CLI: arg parsing, --help/--version, bidirectional conversion. Pure helpers (parseArgs, detectDirection, getDefaultOutputPath) are exported for testability, and an isDirectRun guard prevents main() from running on import.
• package.json — adds the bin entry (cdb-converter → dist/cli.mjs) and @types/sql.js as a devDependency.
• tsup.config.ts — second build entry for the CLI (ESM, shebang preserved).
• src/types.ts — relaxes the SqlDatabase.run param type so a real sql.js Database (typed via @types/sql.js) is structurally assignable to the library's minimal shim, while still accepting the loosely-typed arrays built internally.
• README.md — new CLI section + direction table.
• test/cli.test.ts — unit tests for the CLI helpers.

Notes / follow-ups

Direction is currently inferred from the input extension. A discussed follow-up is to detect the format from magic bytes (CDB 0xFFFFFFFF/0xAAAAAAAA, SQLite "SQLite format 3\0") for robustness against mis-named files — not included here.

[Copilot]

Pull request overview

Adds a Node.js CLI entrypoint (cdb-converter) to run CDB↔SQLite conversions without writing code, integrating it into the package build and adding unit tests for CLI helper logic.

Changes:

• Introduces src/cli.ts with arg parsing, direction detection by extension, and conversion execution.
• Updates build/package metadata to ship an installable cdb-converter binary.
• Adds unit tests for CLI helper functions and relaxes SqlDatabase.run typing for better sql.js compatibility.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tsup.config.ts	Adds a second tsup entry to build the CLI as ESM (dist/cli.mjs).
test/cli.test.ts	Adds Vitest coverage for CLI helper functions (parseArgs, detectDirection, getDefaultOutputPath).
src/types.ts	Widens SqlDatabase.run parameter type to align with sql.js bind params.
src/cli.ts	Implements the CLI command, including help/version output and conversion logic.
README.md	Documents CLI usage and extension-to-direction mapping.
package.json	Adds bin mapping for cdb-converter and includes @types/sql.js in dev deps.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 9 changed files in this pull request and generated 2 comments.