chore: move .github-config to mac/ directory

- Move .github-config from project root to mac/
- Update generate-appcast.sh to reference new location
- Keeps all Mac-specific configuration together

mac/scripts/generate-appcast.sh

@@ -19,7 +19,7 @@ export PATH="$HOME/.local/bin:$PATH"
 
 # Load GitHub configuration
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-CONFIG_FILE="$(dirname "$SCRIPT_DIR")/.github-config"
+CONFIG_FILE="$SCRIPT_DIR/../.github-config"
 if [ -f "$CONFIG_FILE" ]; then
     source "$CONFIG_FILE"
 fi