Add native linux/win binaries to the pipeline

Switch the builder image to rust:1-bookworm — bevy's native linux
build needs glibc + alsa/udev, which does not build against musl —
and add the x86_64-pc-windows-gnu target with mingw-w64 for the
windows cross-compile (linker set from the Makefile, no per-repo
.cargo/config). Mac stays out: darwin needs osxcross, same as the
ebitengine mac plan. Builder steps pull the image on every run so
:latest updates reach the runner.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

example-woodpecker.yaml

@@ -7,9 +7,16 @@ steps:
 
   - name: build
     image: git.teletypegames.org/internal/bevy-builder:latest
+    pull: true
     commands:
       - make ci-export
 
+  - name: binaries
+    image: git.teletypegames.org/internal/bevy-builder:latest
+    pull: true
+    commands:
+      - make ci-binaries
+
   - name: upload
     image: alpine
     environment: