feat: add AZ AIOps Dashboard - optional observability workbook for AI estate

[krishna-sunkavalli]

Summary

Adds the AZ AIOps Dashboard — an Azure Monitor Workbook — as an optional observability component of the AI Landing Zone.

Closes #100

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What this PR adds

New files

File	Description
observability/aiops-dashboard/az-aiops-dashboard.workbook	Azure Monitor Workbook source
observability/aiops-dashboard/azuredeploy.json	ARM template for one-click deployment

README update

Adds an Observability section (between Use cases & Scenarios and Roadmap) with:

• Description of the dashboard and what it monitors
• Filter parameters table
• Deploy to Azure button
• Link to the source repo

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What the workbook shows

Area	Visuals
Overview	Request volume split (AOAI vs Models API), resource map by region, status code trend lines, model-level request bar chart, resource inventory with Diagnostic Settings status
Request Charts	HTTP status code breakdowns — 5xx errors and 429 throttling per API type
Model Usage	Per-model request volumes, top models by usage
Availability	Resource health and availability trends

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Why it fits the AI Landing Zone

• WAF Operational Excellence — observability is a core WAF pillar
• Zero additional infrastructure — consumes the Log Analytics Workspace already provisioned by the landing zone
• No new dependencies — pure Azure Monitor Workbook, no code changes to existing IaC
• One-click deployment — ARM template ready with a Deploy to Azure button

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Testing

1. Deploy the ARM template: observability/aiops-dashboard/azuredeploy.json
2. Open the workbook in Azure Portal > Monitor > Workbooks
3. Set subscription and Log Analytics Workspace parameters
4. Verify all 9 tabs render without errors

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Source repo

https://github.com/krishna-sunkavalli/az-aiops-dashboard