perf(ci): add tmpfs to wheel build runners

Mount /home/runner and /var/lib/docker in RAM for the maturin wheel
builds. Uses r7 (memory-optimized) instances to handle the memory
pressure from tmpfs + Rust compilation.

Co-authored-by: Claude <noreply@anthropic.com>

Author: samantha-earthmover

.github/workflows/python-check.yaml

@@ -26,7 +26,7 @@ defaults:
 
 jobs:
   build-wheels:
-    runs-on: runs-on=${{ github.run_id }}/runner=16cpu-linux-x64/extras=s3-cache
+    runs-on: runs-on=${{ github.run_id }}/runner=16cpu-linux-x64/extras=s3-cache+tmpfs/family=r7
     steps:
       - uses: runs-on/action@742bf56072eb4845a0f94b3394673e4903c90ff0 # v2
         with:
@@ -139,7 +139,7 @@ jobs:
           python -m pytest -n 4 -m "not hypothesis"
 
   build-wheels-free-threaded:
-    runs-on: runs-on=${{ github.run_id }}/runner=16cpu-linux-x64/extras=s3-cache
+    runs-on: runs-on=${{ github.run_id }}/runner=16cpu-linux-x64/extras=s3-cache+tmpfs/family=r7
     steps:
       - uses: runs-on/action@742bf56072eb4845a0f94b3394673e4903c90ff0 # v2
         with: