docs: update golang version reference in copilot-instructions.md to 1.25.9-alpine

Agent-Logs-Url: https://github.com/github/github-mcp-server/sessions/f41eec73-8130-472e-a2d6-ded019a6f506

Co-authored-by: SamMorrowDrums <4811358+SamMorrowDrums@users.noreply.github.com>

Author: Copilot

.github/copilot-instructions.md

@@ -94,7 +94,7 @@ go test ./pkg/github -run TestGetMe
 
 - **go.mod / go.sum:** Go module dependencies (Go 1.24.0+)
 - **.golangci.yml:** Linter configuration (v2 format, ~15 linters enabled)
-- **Dockerfile:** Multi-stage build (golang:1.25.3-alpine → distroless)
+- **Dockerfile:** Multi-stage build (golang:1.25.9-alpine → distroless)
 - **server.json:** MCP server metadata for registry
 - **.goreleaser.yaml:** Release automation config
 - **.gitignore:** Excludes bin/, dist/, vendor/, *.DS_Store, github-mcp-server binary