fix Pi build and CI pipeline ordering

- Fix Pi kernel build: disable includeDefaultModules in initrd.
  NixOS all-hardware.nix includes dw-hdmi which doesn't exist in
  the RPi4 kernel 6.12, causing module-shrunk to fail.
- Fix CI: SD image build now depends on build-hosts instead of
  flake-check, so it won't run if the Pi build fails.
- Apply same fix to raspberry-pi template.

.forgejo/workflows/deploy.yml

@@ -29,7 +29,7 @@ jobs:
         run: nix build .#nixosConfigurations.cryodev-pi.config.system.build.toplevel --impure
 
   build-pi-images:
-    needs: flake-check
+    needs: build-hosts
     runs-on: host
     strategy:
       matrix: