[chore] add MIT license and copyright notices across project files

src/backend.rs

@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025 <COPYRIGHT HOLDER>. All rights reserved.
+
 //! Transcription backend selection and implementations (CPU/GPU) used by PolyScribe.
 use crate::OutputEntry;
 use crate::{decode_audio_to_pcm_f32_ffmpeg, find_model_file};

src/lib.rs

@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025 <COPYRIGHT HOLDER>. All rights reserved.
+
 #![forbid(elided_lifetimes_in_paths)]
 #![forbid(unused_must_use)]
 #![deny(missing_docs)]

src/main.rs

@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025 <COPYRIGHT HOLDER>. All rights reserved.
+
 use std::fs::{File, create_dir_all};
 use std::io::{self, Read, Write};
 use std::path::{Path, PathBuf};

src/models.rs

@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025 <COPYRIGHT HOLDER>. All rights reserved.
+
 //! Model discovery, selection, and downloading logic for PolyScribe.
 use std::collections::BTreeMap;
 use std::env;