meridianstatslisted

<objective> Display comprehensive project statistics: phase and plan completion rates, git commit history, test file counts, planning velocity, and project timeline. </objective> <process> Run the stats command and present the output: ```bash meridian stats ``` If `--json` output is needed for downstream processing: ```bash meridian --json stats ``` The output covers: - **Progress**: phase and plan completion bars with percentages - **Milestones**: per-milestone status and phase counts - **Velocity**: plans completed per day (rolling 7-day window) - **Git**: commit count, total insertions/deletions, file count, last commit date - **Tests**: test file count and test function count - **Timeline**: project start date and age in days If the project has no `.meridian/state.db`, instruct the user to run `meridian init` first. </process> <success_criteria> - [ ] Stats gathered and displayed - [ ] Output readable without additional context </success_criteria>