chore: inital commit

Split project into a Cargo workspace with two crates:

- core/ (noctua_core): UI-independent document library
- ui/ (noctua_ui): COSMIC application scaffold (empty)

justfile for workspace (run, run-cli, check, test, build)

ui/Cargo.toml

@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+# ui/Cargo.toml
+#
+# Binary crate for the Noctua COSMIC desktop application.
+
+[package]
+name = "noctua"
+version = "0.1.0"
+edition = "2021"
+description = "Noctua – a document viewer for the COSMIC™ desktop"
+repository = "https://codeberg.org/wfx/noctua"
+authors = ["Wolfgang Morawetz <wfx@mailbox.org>"]
+license = "GPL-3.0-or-later"
+
+[dependencies]
+noctua_core = { path = "../core" }
+
+# Logging
+log = "0.4"
+env_logger = "0.11"
+
+# i18n / localization
+i18n-embed = { version = "0.16", features = [
+    "fluent-system",
+    "desktop-requester",
+] }
+i18n-embed-fl = "0.10"
+
+# Resource embedding
+rust-embed = "8"
+
+# Open files/URLs with the system default application
+open = "5"
+
+# Async runtime (required by libcosmic)
+tokio = { version = "1", features = ["rt", "rt-multi-thread", "macros"] }
+
+[dependencies.libcosmic]
+git = "https://github.com/pop-os/libcosmic.git"
+features = [
+    "a11y",
+    "about",
+    "dbus-config",
+    "multi-window",
+    "single-instance",
+    "tokio",
+    "winit",
+    "wayland",
+    "wgpu",
+]