clarified the ins and outs of the --since flag on the logs cli command (#340)

<span data-mesa-description="start"></span>
## TL;DR
Clarified the `--since` flag's description for the `logs` CLI command,
specifying supported formats and maximum lookback period.

## Why we made these changes
To improve user clarity and reduce confusion regarding the accepted
duration formats (e.g., 'd' for days vs. 'h' for hours) and the
effective maximum lookback period for the `logs --since` flag.

## What changed?
- **packages/cli/cmd/logs.go**: Updated the `--since` flag's help text
to clearly define supported duration and timestamp formats, explicitly
stating that 'd' for days is not supported and advising the use of hours
instead. The maximum lookback period was also adjusted to 167 hours.

## Validation
- [ ] Verified `cli logs --help` output shows the updated and clarified
description for the `--since` flag.
- [ ] Confirmed the CLI correctly handles `--since` values within the
new 167-hour limit and rejects unsupported formats (like '1d').
<span data-mesa-description="end"></span>

Author: masnwilliams

cmd/logs.go

@@ -20,7 +20,7 @@ var logsCmd = &cobra.Command{
 func init() {
 	logsCmd.Flags().String("version", "latest", "Specify a version of the app (default: latest)")
 	logsCmd.Flags().BoolP("follow", "f", false, "Follow logs in real-time (stream continuously)")
-	logsCmd.Flags().String("since", "s", "How far back to retrieve logs (e.g., 5m, 1h). Defaults to 5m if not following, 5s if following. Can also specify timestamps in formats: 2006-01-02 (day), 2006-01-02T15:04 (minute), 2006-01-02T15:04:05 (second), 2006-01-02T15:04:05.000 (ms), 2006-01-02T15:04:05.000000000 (ns). Maximum is 7d.")
+	logsCmd.Flags().String("since", "s", "How far back to retrieve logs. Supports duration formats: ns, us, ms, s, m, h (e.g., 5m, 2h, 1h30m). Note: 'd' for days is NOT supported - use hours instead. Can also specify timestamps: 2006-01-02 (day), 2006-01-02T15:04 (minute), 2006-01-02T15:04:05 (second), 2006-01-02T15:04:05.000 (ms). Maximum lookback is 167h (just under 7 days). Defaults to 5m if not following, 5s if following.")
 	logsCmd.Flags().Bool("with-timestamps", false, "Include timestamps in each log line")
 	rootCmd.AddCommand(logsCmd)
 }