This commit adds the `libc` dependency to the `Cargo.toml` file for
Unix-based targets. This dependency is required by the `ffmpeg` command
execution within the `recorder` module, specifically for handling
process management and signaling on Unix-like systems.
Introduces new modules for audio recording (`recorder.rs`) and
asynchronous uploading (`uploader.rs`) with retry logic.
The `recorder` module uses `ffmpeg` as a subprocess to capture audio and
save it as M4A files. It handles starting, stopping, and reporting
recording events.
The `uploader` module manages a queue of recordings to be uploaded to
the server. It supports persistent storage of pending uploads via
sidecar JSON files, exponential backoff for retries, and emits events
for UI feedback.
New dependencies were added to `Cargo.toml` and `Cargo.lock` to support
these features, including `reqwest`, `serde_json`, `tokio`, `uuid`, and
`which`.
Brummel