Make ~/.cache writeable

[yarikoptic]

With a not yet merged fix to HOME (#55) which I kept using for days now, I keep running into

● Bash(uvx codespell 2>&1)                                                                                                                                                                                                     
  ⎿  Error: Exit code 2                                                                                                                                                                                                           
     error: Failed to initialize cache at `/home/node/.cache/uv`                                                                                                                                                                  
       Caused by: failed to create directory `/home/node/.cache/uv`: Permission denied (os error 13) 

so claude then creates itself an ephemeral cache under its session /tmp/. We can consider it a "pros" but since it also causes unnecessary "I need to figure things out" I think we should address it one way or another. We could

• bind mount ~/.cache rw -- efficient but helps to break isolation
• bind mount dedicated TMPDIR folder as ~/.cache -- similar to what we do in https://github.com/ReproNim/containers/blob/master/scripts/singularity_cmd for tmpdir (there it is singularity so no ephemeral "inside" tmp)
• symlink ~/.cache to pre-created in podman /tmp/caches -- so would still be under /tmp/ but "transparent"

WDYT @asmacdo ?