Add idempotent dashboard apply

[jsierles]

Dashboard and log configuration audits need safe, replayable CLI paths so agents do not fall back to raw API calls or manual UI interpretation.

Changes

• Add idempotent JSON dashboard apply with duplicate-title safety
• Add read-only log index list/get/order commands with exclusions and retention
• Add read-only log pipeline list/get/order commands with complete processors
• Surface bounded Datadog API validation errors
• Document permissions, workflows, and stable JSON output
• Cover parsing, filtering, title matching, and diagnostics with unit tests

First consumer: zooglerails PR #26007.

Assisted-by: Cursor (gpt-5.6-sol-medium)