Update skills for Postgres parameter CLI

[cursor]

Changelog entry

• https://planetscale.com/changelog/postgres-branch-parameters-cli

What changed

• Added read-only inventory guidance for pscale branch parameters list, including JSON output, namespace filtering, and restart-requirement evidence.
• Added CLI automation guidance for queuing Postgres parameter changes through pscale branch resize --parameters, plus status and cancel commands.
• Updated Postgres safety, Query Insights, and best-practices guidance so parameter inspection and changes account for the new CLI surface alongside dashboard/API/Terraform workflows.

Why

PlanetScale now exposes Postgres cluster parameter inspection and updates through the pscale CLI. The skills should guide agents to use the read-only command for evidence and treat parameter changes as approval-gated operational actions, especially when a change requires a restart.

Verification

• Confirmed no async setup was running.
• Confirmed the working tree was clean after commit/push.
• Confirmed the updated command guidance appears in the affected SKILL.md files with rg.