refactor(commit-ai): remove local models and simplify AI flow

Remove local on-device model support and related IPC commands,
consolidating commit-generation to cloud providers and simplifying the
AI crate surface. Local-specific types, generation profiles, caching,
and the local prompt builder were removed while message sanitization and
diff-echo detection were preserved. Also harden repository handling and
runtime: unborn HEADs are handled gracefully so empty repos still report
files, Git LFS sync is skipped for repositories without commits, and
tokio runtime features were enabled.

- Remove local model engine, load/status commands, and local profile code
- Handle unborn HEAD and skip LFS sync for repos without commits
- Enable tokio runtime features and route AI generation to cloud only

src-tauri/src/main.rs

@@ -14,24 +14,23 @@ use git::{
     SearchCancellationState, add_remote, add_to_gitignore, add_worktree, amend_commit,
     apply_file_patch, cancel_code_search, cancel_file_history, checkout_branch, cherry_pick_abort,
     cherry_pick_commit, cherry_pick_continue, clone_repository, commit, commit_ai_generate,
-    commit_ai_load, commit_ai_local_models, commit_ai_review, commit_ai_split, commit_ai_status,
-    compare_commits, compare_file_to_head, compare_file_to_parent, create_branch, create_tag,
-    cred_delete, cred_load, cred_save, delete_branch, delete_commit_note, delete_remote_branch,
-    delete_remote_branches, delete_tag, diff_file_against_working_tree, fetch, fetch_commit_notes,
-    get_commit_note, get_file_blame, get_file_patch, get_remote_url, get_status, git_lfs_install,
-    git_lfs_prune, git_lfs_pull, git_lfs_status, git_lfs_track, git_lfs_untrack, init_repository,
-    last_commit_message, list_branches, list_commits, list_file_history,
-    list_interactive_rebase_commits, list_reflog, list_remotes, list_repository_files,
-    list_stashes, list_tags, list_worktrees, lock_worktree, merge_abort, merge_branch,
-    merge_continue, move_worktree, open_repo_in_explorer, open_repository, open_repository_bundle,
-    open_repository_file, prune_worktrees, pull, push, push_commit_notes, push_tag, read_conflict,
-    rebase_abort, rebase_branch, rebase_continue, remove_remote, remove_worktree, rename_branch,
-    rename_remote_branch, repair_worktree, resolve_conflict, resolve_conflict_side,
-    restore_file_from_commit, restore_files, restore_reflog_entry, restore_to_commit,
-    revert_commit, run_sequence_editor_if_requested, search_code_introductions,
-    set_branch_upstream, set_commit_note, stage_files, start_interactive_rebase, stash_apply,
-    stash_drop, stash_pop, stash_push, undo_last_commit, unlock_worktree, unstage_files,
-    untrack_paths, update_remote,
+    commit_ai_review, commit_ai_split, compare_commits, compare_file_to_head,
+    compare_file_to_parent, create_branch, create_tag, cred_delete, cred_load, cred_save,
+    delete_branch, delete_commit_note, delete_remote_branch, delete_remote_branches, delete_tag,
+    diff_file_against_working_tree, fetch, fetch_commit_notes, get_commit_note, get_file_blame,
+    get_file_patch, get_remote_url, get_status, git_lfs_install, git_lfs_prune, git_lfs_pull,
+    git_lfs_status, git_lfs_track, git_lfs_untrack, init_repository, last_commit_message,
+    list_branches, list_commits, list_file_history, list_interactive_rebase_commits, list_reflog,
+    list_remotes, list_repository_files, list_stashes, list_tags, list_worktrees, lock_worktree,
+    merge_abort, merge_branch, merge_continue, move_worktree, open_repo_in_explorer,
+    open_repository, open_repository_bundle, open_repository_file, prune_worktrees, pull, push,
+    push_commit_notes, push_tag, read_conflict, rebase_abort, rebase_branch, rebase_continue,
+    remove_remote, remove_worktree, rename_branch, rename_remote_branch, repair_worktree,
+    resolve_conflict, resolve_conflict_side, restore_file_from_commit, restore_files,
+    restore_reflog_entry, restore_to_commit, revert_commit, run_sequence_editor_if_requested,
+    search_code_introductions, set_branch_upstream, set_commit_note, stage_files,
+    start_interactive_rebase, stash_apply, stash_drop, stash_pop, stash_push, undo_last_commit,
+    unlock_worktree, unstage_files, untrack_paths, update_remote,
 };
 use integrations::list_integration_repositories;
 use std::path::{Path, PathBuf};
@@ -317,7 +316,6 @@ async fn main() {
         .manage(StartupRepository(Mutex::new(startup_repository)))
         .manage(StartupClone(Mutex::new(startup_clone)))
         .manage(SearchCancellationState::default())
-        .manage(commit_ai::CommitAiEngine::new())
         .plugin(tauri_plugin_dialog::init());
 
     // Linux installs are expected to come from the system package manager (see the
@@ -388,9 +386,6 @@ async fn main() {
             amend_commit,
             undo_last_commit,
             last_commit_message,
-            commit_ai_status,
-            commit_ai_load,
-            commit_ai_local_models,
             commit_ai_generate,
             commit_ai_review,
             commit_ai_split,