Add config/allowlist.yaml — YAML-driven gate that auto-approves bounded
tool calls when no human is present.
When Timmy runs with --autonomous or stdin is not a terminal, tool calls
are checked against allowlist: matched → auto-approved, else → rejected.
Changes:
- config/allowlist.yaml: shell prefixes, deny patterns, path rules
- tool_safety.py: is_allowlisted() checks tools against YAML rules
- cli.py: --autonomous flag, _is_interactive() detection
- 44 new allowlist tests, 8 updated CLI tests
Closes#69