Refactor to Cargo Workspace (#129)

* Refactor project into a Cargo workspace with distinct packages

- Created a root `Cargo.toml` defining a workspace.
- Moved `src/types` and `src/utils` into a new `pwsp-lib` crate for shared logic.
- Split binaries into their own crates: `pwsp-daemon`, `pwsp-cli`, and `pwsp-gui`.
- Shifted all dependencies into `[workspace.dependencies]` for centralized version management.
- Updated import paths across all crates (e.g. from `pwsp::` to `pwsp_lib::`).
- Updated build scripts, GitHub actions, Flatpak manifest, and AUR PKGBUILD to support the new workspace structure.
- Ensured no core application logic was altered.

Co-authored-by: arabianq <55220741+arabianq@users.noreply.github.com>

* Fix cargo-deb build process in GitHub actions for workspace architecture

Co-authored-by: arabianq <55220741+arabianq@users.noreply.github.com>

* Fix cargo-deb asset discovery by using exact target/release paths

Co-authored-by: arabianq <55220741+arabianq@users.noreply.github.com>

* refactor deps in Cargo.toml files

* fix incorrect assets path

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

pwsp-lib/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "pwsp-lib"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+homepage.workspace = true
+repository.workspace = true
+license.workspace = true
+
+[dependencies]
+tokio.workspace = true
+async-trait.workspace = true
+
+serde.workspace = true
+serde_json.workspace = true
+
+dirs.workspace = true
+itertools.workspace = true
+evdev.workspace = true
+anyhow.workspace = true
+rustix.workspace = true
+
+rodio.workspace = true
+pipewire.workspace = true
+
+egui.workspace = true
+
+reqwest.workspace = true