Decouple core Yaak logic from Tauri (#354)

crates/yaak-git/src/init.rs

@@ -0,0 +1,14 @@
+use crate::error::Result;
+use crate::repository::open_repo;
+use log::info;
+use std::path::Path;
+
+pub fn git_init(dir: &Path) -> Result<()> {
+    git2::Repository::init(dir)?;
+    let repo = open_repo(dir)?;
+    // Default to main instead of master, to align with
+    // the official Git and GitHub behavior
+    repo.set_head("refs/heads/main")?;
+    info!("Initialized {dir:?}");
+    Ok(())
+}