feat(status): add status subcommand with day and week metrics

- Add status.py with compute_day_status() and compute_week_status()
- Add projected_hours_for_day(): for each entry, use its duration if
  closed, or the next entry's start time as the close time if open
- Open entries (start present, end absent) are preserved by the parser
  instead of being skipped; aggregate_rows() skips them for summaries
- Expected end is computed by filling remaining hours into available
  time slots from the open entry's start; clamped to latest_end if a
  pre-logged entry ends later, with a note explaining why
- Projected week total sums projected_hours_for_day() across all days
- Add status subcommand to cli.py with shared source/day arguments
- Add [work] daily_hours / weekly_hours config keys (default 8 / 40)
- Add timesheets.example.toml [work] section
- Add tests for projected_hours_for_day, compute_day_status,
  compute_week_status and all DayStatus/WeekStatus fields

timesheets.example.toml

@@ -3,3 +3,7 @@ token = "your_api_token_here"
 
 [projects]
 map = "/path/to/project_map.json"
+
+[work]
+daily_hours = 8.0
+weekly_hours = 40.0