fix: expose custom packages as flake outputs for CI caching

Add packages output with:
- custom-* packages from packages/
- qt-pinned-jellyfin-media-player

Update CI to use hyphenated names (flake attrs can't have dots)

flake.nix

@@ -234,6 +234,28 @@
       ];
     };
 
+    # Packages for CI caching (custom packages and qt-pinned)
+    packages = nixpkgs.lib.genAttrs [ "x86_64-linux" "aarch64-linux" ] (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          config.allowUnfree = true;
+          overlays = [ (mkBaseOverlay {}) ];
+        };
+        pkgsQt = import inputs.nixpkgs-qt {
+          inherit system;
+          config.allowUnfree = true;
+        };
+      in {
+        "custom-claude-code" = pkgs.custom.claude-code;
+        "custom-app-launcher-server" = pkgs.custom.app-launcher-server;
+        "custom-mcrcon-rbw" = pkgs.custom.mcrcon-rbw;
+        "custom-tea-rbw" = pkgs.custom.tea-rbw;
+        "custom-rclone-torbox-setup" = pkgs.custom.rclone-torbox-setup;
+        "qt-pinned-jellyfin-media-player" = pkgsQt.jellyfin-media-player;
+      }
+    );
+
     # Flake apps
     apps = nixpkgs.lib.genAttrs [ "x86_64-linux" "aarch64-linux" "aarch64-darwin" ] (system:
       let