chore: add pure-Go SQLite support via build tags for Windows compatibility

[tejasva-vardhan]

Problem

Setting up Maglev on Windows currently requires a complex CGO toolchain (GCC/MinGW) because of the mattn/go-sqlite3 dependency. This creates a high barrier to entry for new contributors on Windows.

Proposed Solution

I propose adding a pure-Go SQLite driver (modernc.org/sqlite) as an alternative using Go build tags.

• Create driver_cgo.go (with //go:build !windows || cgo tag).
• Create driver_pure.go (with //go:build windows && !cgo tag).

This ensures that:

1. Production/Linux builds remain unaffected (still using CGO).
2. Windows developers can run go run ./cmd/api without any extra setup.

I have already verified this locally and would like to submit a PR if this approach aligns with the project goals.

[ARCoder181105]

Hi @tejasva-vardhan ,

Thanks for the great suggestion!

We actually already have modernc.org/sqlite integrated into the project, but it currently requires developers to manually pass a custom build flag (-tags purego).

Your proposed tags (windows && !cgo and !windows || cgo) are a massive improvement. Making the pure-Go fallback automatic for Windows developers without needing extra flags is exactly what we need.

We would love to see a PR to update these tags! Please feel free to submit one.