feat: Add --verbose / --debug CLI flags for logging control

[yokoszn]

Summary

Add stackable verbosity flags (-v, -vv, -vvv) and a --debug shortcut to control logging output, enabling better debugging of agent behavior and LLM interactions.

Use Case

Currently, Strix has limited visibility into runtime behavior. Users troubleshooting issues need:

• Ability to increase log verbosity for debugging
• LLM request/response logging for diagnosing model issues
• Persistent log files for post-run analysis

Proposed Behavior

Flag	Level	stderr	File
(none)	ERROR	yes	no
-v	WARNING	yes	yes
-vv	INFO	yes	yes
-vvv / --debug	DEBUG	yes	yes

• Log files written to strix_runs/{run_name}/debug.log when verbosity > 0
• At -vvv/--debug, enable litellm verbose mode for LLM debugging

Implementation Considerations

• Must handle existing logging.getLogger().setLevel(logging.ERROR) at module level
• litellm debugging toggle needs to use correct API (litellm._logging._enable_debugging())
• Consider log rotation for long-running sessions
• Add tests for verbosity levels

Related

PR #140 implements this feature