Add pscale metrics commands

[dgraham]

Query performance metrics for a branch. Includes a comprehensive metrics report command that includes all metrics relevant to each kind of database (Vitess, PostgreSQL).

• pscale metrics show <database> <branch> --org <org> --metric queries --metric latency_p99 --period 1h
• pscale metrics instant <database> <branch> --org <org> --metric planetscale_volume_usage_percentage
• pscale metrics report <database> <branch> --org <org> --period 1d

Sample output

$ pscale metrics show <database> <branch> --org <org> --metric queries --metric latency_p99 --period 1h

  Metrics for <database>/<branch>
  Range: 2026-08-18 10:00–11:00 MDT · interval: 60s · up to 60 points/series

  METRIC        SERIES  DIMENSIONS  LATEST    MIN       AVG       MAX       TREND
  Queries       —       —           1,903     912       1,366     1,903     ▁▄█
  Latency p99   —       —           18.24 ms  7.821 ms  12.46 ms  18.24 ms  ▁▅█

  $ pscale metrics instant <database> <branch> --org <org> --metric planetscale_volume_usage_percentage

  Current metrics for <database>/<branch>

  METRIC        DIMENSIONS                    VALUE
  Volume usage  pod=postgres-0, role=primary  71.4%
  Volume usage  pod=postgres-1, role=replica  68.25%

  $ pscale metrics report <database> <branch> --org <org> --period 1d

  Metrics report for <org>/<database>/<branch>
  Range: 2026-08-17 11:00–2026-08-18 11:00 MDT · interval: 900s

  Workload, errors, and traffic control

  METRIC        SERIES  DIMENSIONS  LATEST  MIN  AVG    MAX    TREND
  Queries       —       —           1,903   912  1,366  2,104  ▁▃▅▄▆█
  Query errors  —       —           3       0    1.25   7      ▁▁▂▁▃█

  Latency and execution time

  METRIC       SERIES  DIMENSIONS  LATEST    MIN       AVG       MAX       TREND
  Latency p50  —       —           2.184 ms  1.702 ms  2.056 ms  2.831 ms  ▁▃▄█
  Latency p99  —       —           18.24 ms  7.821 ms  12.46 ms  24.19 ms  ▁▂▅█

  ...

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, have a team admin enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 540fff4. Configure here.}