feat: implement default Git identity management and local identity check

packages/desktop/src-tauri/Cargo.lock

@@ -2977,7 +2977,7 @@ dependencies = [
 
 [[package]]
 name = "openchamber-desktop"
-version = "1.4.8"
+version = "1.4.9"
 dependencies = [
  "anyhow",
  "axum",

packages/desktop/src-tauri/src/commands/git.rs

@@ -2029,6 +2029,27 @@ pub async fn get_current_git_identity(
     })
 }
 
+#[tauri::command]
+pub async fn has_local_identity(
+    directory: String,
+    state: State<'_, DesktopRuntime>,
+) -> Result<bool, String> {
+    let root = validate_git_path(&directory, state.settings())
+        .await
+        .map_err(|e| e.to_string())?;
+
+    let user_name = run_git(&["config", "--local", "--get", "user.name"], &root)
+        .await
+        .ok()
+        .filter(|s| !s.is_empty());
+    let user_email = run_git(&["config", "--local", "--get", "user.email"], &root)
+        .await
+        .ok()
+        .filter(|s| !s.is_empty());
+
+    Ok(user_name.is_some() || user_email.is_some())
+}
+
 #[tauri::command]
 pub async fn get_global_git_identity() -> Result<GitIdentitySummary, String> {
     let user_name = tokio::process::Command::new("git")

packages/desktop/src-tauri/src/commands/settings.rs

@@ -257,6 +257,14 @@ fn sanitize_settings_update(payload: &Value) -> Value {
                 result_obj.insert("defaultAgent".to_string(), json!(trimmed));
             }
         }
+        if let Some(Value::String(s)) = obj.get("defaultGitIdentityId") {
+            let trimmed = s.trim();
+            if trimmed.is_empty() {
+                result_obj.insert("defaultGitIdentityId".to_string(), Value::Null);
+            } else {
+                result_obj.insert("defaultGitIdentityId".to_string(), json!(trimmed));
+            }
+        }
         if let Some(Value::String(s)) = obj.get("commitMessageModel") {
             let trimmed = s.trim();
             if trimmed.is_empty() {

packages/desktop/src-tauri/src/main.rs

@@ -33,7 +33,7 @@ use commands::git::{
     add_git_worktree, check_is_git_repository, checkout_branch, create_branch, create_git_commit, rename_branch,
     create_git_identity, delete_git_branch, delete_git_identity, delete_remote_branch,
     discover_git_credentials, ensure_openchamber_ignored, generate_commit_message, get_commit_files,
-    get_current_git_identity, get_git_branches, get_git_diff, get_git_file_diff,
+    get_current_git_identity, has_local_identity, get_git_branches, get_git_diff, get_git_file_diff,
     get_git_identities, get_git_log, get_git_status, get_global_git_identity, get_remote_url,
     git_fetch, git_pull, git_push, is_linked_worktree, list_git_worktrees, remove_git_worktree,
     revert_git_file, set_git_identity, update_git_identity,
@@ -871,6 +871,7 @@ fn main() {
             update_git_identity,
             delete_git_identity,
             get_current_git_identity,
+            has_local_identity,
             get_global_git_identity,
             get_remote_url,
             set_git_identity,

packages/desktop/src/api/git.ts

@@ -218,6 +218,14 @@ export const createDesktopGitAPI = (): GitAPI => ({
     }
   },
 
+  async hasLocalIdentity(directory: string): Promise<boolean> {
+    try {
+      return await safeGitInvoke<boolean>('has_local_identity', { directory });
+    } catch {
+      return false;
+    }
+  },
+
   async setGitIdentity(directory: string, profileId: string): Promise<{ success: boolean; profile: GitIdentityProfile }> {
     const profile = await safeGitInvoke<GitIdentityProfile>('set_git_identity', { directory, profileId });
     return { success: true, profile };