refactor(deps): replace git2 with system git and add vcs support

src/core/vcs/mod.rs

@@ -0,0 +1,61 @@
+// DCR — Cargo-like C/C++ project manager.
+//
+// Copyright (C) 2026 Dexoron (Bezotechestvo Vladimir) <main@dexoron.su>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub mod git;
+
+use std::path::Path;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum VcsKind {
+    Git,
+    None,
+}
+
+impl VcsKind {
+    pub fn parse(s: &str) -> Result<Self, String> {
+        match s.to_lowercase().as_str() {
+            "git" => Ok(Self::Git),
+            "none" => Ok(Self::None),
+            _ => Err(format!("Unknown VCS: {}", s)),
+        }
+    }
+}
+
+pub fn init_vcs(kind: VcsKind, path: &Path) -> Result<(), String> {
+    match kind {
+        VcsKind::Git => git::init(path),
+        VcsKind::None => Ok(()),
+    }
+}
+
+// look for git repo in parents to avoid nested repos
+pub fn find_existing_vcs(path: &Path) -> Option<VcsKind> {
+    let mut current = if path.is_file() {
+        path.parent()
+    } else {
+        Some(path)
+    };
+
+    while let Some(dir) = current {
+        if dir.join(".git").exists() {
+            return Some(VcsKind::Git);
+        }
+        current = dir.parent();
+    }
+
+    None
+}