Add restore_commit and restore_file commands to IPC socket API

[barissalihbabacan]

Problem

Desktop clients and CLI tools communicating over /tmp/osmos-daemon.sock cannot trigger file or tree restoration because the wire protocol lacks restore commands.

Proposed Solution

Add to crates/osmos-daemon/src/api.rs and handler.rs:

• Command::RestoreCommit { path: String, commit_id: Uuid }
• Command::RestoreFile { path: String, commit_id: Uuid, file_path: String }

Acceptance Criteria

• Daemon JSON IPC responds with {"ok": true, "restored": true} upon successful restore.
• Returns structured error COMMIT_NOT_FOUND or BLOB_NOT_FOUND if reference is missing.