Both multiline and single-line input paths in interactive.rs had identical
code for:
- Template processing (process_template)
- Task execution (execute_task_with_retry)
- Auto-memory reminder with error handling
Extracted to a single execute_user_input() helper function that handles
all three steps. This eliminates code-path aliasing where the two paths
could drift over time.
File reduced from 401 to 393 lines (-2%).
All 106 g3-cli tests pass.
Agent: fowler
d6a986ce0f