TH-3418: add end-to-end agent testing and production quality monitoring cookbooks

[KarthikAvinashFI]

Summary

Adds two new use-case cookbooks under src/pages/docs/cookbook/use-cases/:

• end-to-end-agent-testing: full agent lifecycle walkthrough using FutureAGI's complete stack — define the agent, use Simulate to generate 100 diverse conversations, run Evals to score quality, diagnose with Agent Compass + Fix My Agent, run Optimize to rewrite the system prompt based on the failures, add Protect guardrails, and wire it into Observe.
• production-quality-monitoring: monitoring pipeline using Observe for tracing, inline Evals for quality scoring, Alerts for latency/error spikes, Agent Compass for failure clustering, and Protect as the final safety gate.

Both cookbooks are written as narrative walkthroughs with real screenshots and analysis from actual runs, not placeholder data.

Test plan

• Astro preview renders both pages without MDX errors
• All image and video URLs (S3) load correctly
• Step numbering, code blocks, and tables render as expected
• Internal links to other cookbook pages resolve