Refactor GUI backend config to constants.py

Extracts the hardcoded BeeWare GUI backend configuration (package names, versions, and SHA256 hashes) from `src/seedpass/cli/__init__.py` into a new `GUI_BACKEND_CONFIG` dictionary in `src/constants.py`. This improves maintainability by centralizing configuration and simplifying the CLI logic.

- Adds `GUI_BACKEND_CONFIG` to `src/constants.py`.
- Updates `src/seedpass/cli/__init__.py` to import and use `GUI_BACKEND_CONFIG`.

Co-authored-by: PR0M3TH3AN <[email protected]>

src/constants.py

@@ -55,6 +55,27 @@ INACTIVITY_TIMEOUT = 15 * 60  # 15 minutes
 # Duration in seconds that a notification remains active
 NOTIFICATION_DURATION = 10
 
+# -----------------------------------
+# GUI Backend Configuration
+# -----------------------------------
+GUI_BACKEND_CONFIG = {
+    "linux": {
+        "pkg": "toga-gtk",
+        "version": "0.5.2",
+        "sha256": "15b346ac1a2584de5effe5e73a3888f055c68c93300aeb111db9d64186b31646",
+    },
+    "win32": {
+        "pkg": "toga-winforms",
+        "version": "0.5.2",
+        "sha256": "83181309f204bcc4a34709d23fdfd68467ae8ecc39c906d13c661cb9a0ef581b",
+    },
+    "darwin": {
+        "pkg": "toga-cocoa",
+        "version": "0.5.2",
+        "sha256": "a4d5d1546bf92372a6fb1b450164735fb107b2ee69d15bf87421fec3c78465f9",
+    },
+}
+
 # -----------------------------------
 # Additional Constants (if any)
 # -----------------------------------

src/seedpass/cli/__init__.py

@@ -10,6 +10,7 @@ import typer
 
 from .common import _get_services
 from seedpass.core.errors import SeedPassError
+from constants import GUI_BACKEND_CONFIG
 
 app = typer.Typer(
     help="SeedPass command line interface",
@@ -110,25 +111,20 @@ def gui(
     confirmation.
     """
     if not _gui_backend_available():
-        if sys.platform.startswith("linux"):
-            pkg = "toga-gtk"
-            version = "0.5.2"
-            sha256 = "15b346ac1a2584de5effe5e73a3888f055c68c93300aeb111db9d64186b31646"
-        elif sys.platform == "win32":
-            pkg = "toga-winforms"
-            version = "0.5.2"
-            sha256 = "83181309f204bcc4a34709d23fdfd68467ae8ecc39c906d13c661cb9a0ef581b"
-        elif sys.platform == "darwin":
-            pkg = "toga-cocoa"
-            version = "0.5.2"
-            sha256 = "a4d5d1546bf92372a6fb1b450164735fb107b2ee69d15bf87421fec3c78465f9"
-        else:
+        platform_key = "linux" if sys.platform.startswith("linux") else sys.platform
+        backend_info = GUI_BACKEND_CONFIG.get(platform_key)
+
+        if not backend_info:
             typer.echo(
                 f"Unsupported platform '{sys.platform}' for BeeWare GUI.",
                 err=True,
             )
             raise typer.Exit(1)
 
+        pkg = backend_info["pkg"]
+        version = backend_info["version"]
+        sha256 = backend_info["sha256"]
+
         if not install:
             typer.echo(
                 f"BeeWare GUI backend not found. Please install {pkg} manually or rerun "