fix(remote): validate remote URL, name and refspecs

Call validate_remote_url, validate_ref_name, and validate_refspec before
passing user input to git subprocess in update_remote_mirror, fetch_remote,
and create_repository_from_url.

remote/mirror.rs

@@ -8,13 +8,18 @@ impl GitBare {
         &self,
         request: UpdateRemoteMirrorRequest,
     ) -> GitResult<UpdateRemoteMirrorResponse> {
+        crate::sanitize::validate_remote_url(&request.remote_url)?;
+
         let remote_name = if request.remote_name.is_empty() {
             "origin"
         } else {
             &request.remote_name
         };
+        crate::sanitize::validate_ref_name(remote_name)?;
+        for rs in &request.refspecs {
+            crate::sanitize::validate_refspec(rs)?;
+        }
 
-        // Add or update remote
         let remote_check = std::process::Command::new("git")
             .args([
                 "--git-dir",
@@ -26,7 +31,6 @@ impl GitBare {
             .output();
 
         if remote_check.is_err() || !remote_check.unwrap().status.success() {
-            // Add new remote
             std::process::Command::new("git")
                 .args([
                     "--git-dir",
@@ -42,7 +46,6 @@ impl GitBare {
                     stderr: e.to_string(),
                 })?;
         } else {
-            // Update existing remote URL
             std::process::Command::new("git")
                 .args([
                     "--git-dir",
@@ -59,7 +62,6 @@ impl GitBare {
                 })?;
         }
 
-        // Fetch
         let mut fetch_args = vec![
             "--git-dir".to_string(),
             self.bare_dir.to_string_lossy().into_owned(),
@@ -129,13 +131,18 @@ impl GitBare {
 
     /// Fetch from a remote URL without mirroring.
     pub fn fetch_remote(&self, request: FetchRemoteRequest) -> GitResult<FetchRemoteResponse> {
+        crate::sanitize::validate_remote_url(&request.remote_url)?;
+
         let remote_name = if request.remote_name.is_empty() {
             "origin"
         } else {
             &request.remote_name
         };
+        crate::sanitize::validate_ref_name(remote_name)?;
+        for rs in &request.refspecs {
+            crate::sanitize::validate_refspec(rs)?;
+        }
 
-        // Ensure remote exists
         let exists = std::process::Command::new("git")
             .args([
                 "--git-dir",
@@ -213,6 +220,8 @@ impl GitBare {
 
     /// Clone a repository from a remote URL (bare + mirror).
     pub fn create_repository_from_url(&self, remote_url: &str, mirror: bool) -> GitResult<()> {
+        crate::sanitize::validate_remote_url(remote_url)?;
+
         let mut args = vec!["clone".to_string()];
         args.push("--bare".to_string());
         if mirror {