Manage platform's merge-queue ruleset at a 90-minute timeout #318

🤖 Generated by the Agentic Engineer

Problem

platform's "Require merge queue" rule is imported read-only here, so its 60-minute check timeout cannot be changed from this repository. In 30 days two platform pull requests were evicted from the queue for timing out while waiting on a runner or behind a failing group (measured on devantler-tech/platform#3097).

Evidence

A disabled probe copy on platform-template (#316, #317) showed that the provider keeps the rule's admin bypass under Update and does not re-apply the rule across reconciles.

Acceptance criteria

• platform's merge-queue rule is managed with Observe + Update, the full live rule declared, and a 90-minute timeout.
• After release, GitHub reports timeout 90 and the OrganizationAdmin bypass unchanged.
• The disposable probe ruleset is removed from platform-template.

Part of devantler-tech/platform#3097