SSH key mounting was broken because:
1. Each selected key was mounted to a separate source dir but all targeted
the same ~/.ssh path in the container, causing Docker Compose's
last-mount-wins behavior
2. All keys were named id_ed25519, so they'd overwrite each other
Changes:
- ssh_keys.py: add key_filename param to prepare_ssh_key_files for unique
key names; add write_ssh_config for combined multi-key config
- tool_instances.py: collect all selected keys into a single ~/.ssh mount
with sanitized unique filenames (id_ed25519_<name>); generate combined
SSH config with all IdentityFile entries
- tests: add os.makedirs mock for SSH permission tests
Quality gates: pytest (19 passed, 1 skipped)
Alex Blank
c6b804bf0a