gh run view --log: strip runner boilerplate, surface script output

What

rtk gh run view <id> --log and --log-failed pass through raw GHA log output without filtering. Runner setup boilerplate (provisioner, image version, region, permissions) dominates — actual script content is buried.

Example

rtk gh run view 23733040015 --repo WILSCH-AI-SERVICES/archibus-bulk-import --log-failed

First 30 lines are all runner setup (provisioner version, Azure region, Ubuntu version, image SHA, permissions). The actual validation output (container_name: found — breaks isolation) is at line 217 of 234.

Expected

RTK should strip:

• Runner provisioner/image/version/region lines
• ##[group]/##[endgroup] markers and content between them (when it's setup, not script output)
• GITHUB_TOKEN Permissions block
• Secret source / Prepare workflow / Download action / Getting action download info lines
• Post-job cleanup (git config, orphan process cleanup, token revocation)
• ANSI escape sequences ([36;1m, [0m)
• UNKNOWN STEP label (replace with step name if extractable)

Surfacing only the actual script output.

Impact

gh run view --log is one of the most token-expensive gh commands. A 500-line log typically has ~50 lines of actual content — 10x context waste in AI agent workflows reading GHA deploy logs.