feat(claude): add release payload job management commands

[stbenjam]

Add slash commands for managing OpenShift release payload jobs:

• /payload-job-promote - promote informing to blocking
• /payload-job-demote - demote blocking to informing
• /payload-job-aggregate - enable statistical analysis
• /payload-job-deaggregate - disable statistical analysis

Updates .gitignore to track .claude/ commands.

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: stbenjam
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[openshift-ci-robot]

[REHEARSALNOTIFIER]
@stbenjam: no rehearsable tests are affected by this change

[openshift-ci]

@stbenjam: all tests passed!

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