Sandbox: shell completions and tests

[mathiasbourgoin]

Summary

Shell completions for the new sandbox CLI commands and tests for the yes-wallet and sandbox libraries.

Blocked by: #780 (sandbox CLI commands)

Changes

Shell completions

• Run make completions after CLI changes
• Add bash/zsh completions for sandbox subcommands (create, list, status, start, stop, destroy, add-account)

Unit tests for yes-wallet

• Test secret_key_for_prefix returns correct hardcoded key for all PKH types (tz1, tz2, tz3, tz4)
• Test write_wallet produces valid JSON matching octez-client format
• Test round-trip: write_wallet → Keys_reader.read_keys_full can parse the output

Unit tests for sandbox config

• Test name resolution (auto-naming, custom naming, duplicate detection)
• Test config validation (required fields, valid RPC address format)

Integration tests (if feasible)

• Test sandbox create with --dry-run or mock node (if applicable)
• Test destroy cleans up all resources

Verification

• dune build && dune runtest
• Shell completions include sandbox subcommands
• All new tests pass