[instructions] Sync github-agentic-workflows.md with v0.47.1

[github-actions]

Instructions Update - Synchronized with v0.47.1

This PR updates the github-agentic-workflows.md instructions file to reflect the addition of the Google Gemini CLI engine in v0.47.0, which shipped in the v0.47.1 release.

Changes Made

• engine: string format: Added "gemini" as a valid option (experimental, requires GEMINI_API_KEY secret)
• engine: object format: Updated id: comment to list gemini alongside copilot, claude, codex
• Firewall notes (3 locations): Updated from "Copilot engine only" → "Copilot and Gemini engines" since GeminiEngine.supportsFirewall = true
• gh aw logs --engine: Added --engine gemini to the log filter examples
• Validation error example: Updated enum example to include "gemini"

Documentation Commits Reviewed

• 3064a1a feat: Add Google Gemini CLI as experimental agentic engine (feat: Add Google Gemini CLI as experimental agentic engine #16894) — added gemini to schema enum
• a280a6b fix: Gemini engine uses .gemini/settings.json instead of unsupported --mcp-config flag (fix: Gemini engine uses .gemini/settings.json instead of unsupported --mcp-config flag #16938) — post-release bug fix

Validation

• Followed prompting best practices (imperative mood, minimal examples)
• Maintained technical tone and brevity
• Updated only necessary sections
• Verified accuracy against current codebase (GeminiEngine.supportsFirewall = true, schema enum updated)
• Removed outdated or redundant content (merged two bullet points about firewall support)

AI generated by Instructions Janitor

• expires on Feb 22, 2026, 12:00 AM UTC