agent/auth: Implement agent authentication #104

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Status	Duration	Name
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✅ Succeeded	9 seconds	prefetch-dependencies
✅ Succeeded	2 minutes	build-container
✅ Succeeded	7 seconds	build-image-index
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✅ Succeeded	8 seconds	push-dockerfile
✅ Succeeded	14 seconds	ecosystem-cert-preflight-checks
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✅ Succeeded	13 seconds	deprecated-base-image-check
✅ Succeeded	9 seconds	sast-snyk-check
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