Azure VM + Azure ML support

[maksimov]

Add Microsoft Azure as a GPU provider. Looking for contributors with Azure experience — I don't have access to Azure so can't test this myself.

What to implement

A new internal/providers/azure/ package following the same pattern as internal/providers/aws/:

Discovery

• Azure GPU VMs — NC-series (T4), ND-series (A100, H100), NV-series (A10)
• Azure ML endpoints — managed GPU inference endpoints

Metrics

• Azure Monitor — CPU utilization, GPU utilization (via NVIDIA GPU monitoring extension or Azure Monitor GPU metrics), network I/O

Pricing

• Add Azure GPU VM specs to internal/pricing/ (on-demand + Spot prices)

How the codebase works

The existing analysis rules in internal/analysis/rules.go are provider-agnostic — they operate on models.GPUInstance. Once an Azure provider populates the same struct, all 9 rules work automatically.

Key files to reference:

• internal/providers/aws/ec2.go — EC2 discovery pattern to follow
• internal/providers/aws/cloudwatch.go — metrics enrichment pattern
• internal/models/models.go — GPUInstance struct and Source type (add SourceAzureVM, SourceAzureML)
• cmd/gpuaudit/main.go — CLI wiring (add --skip-azure flag, call provider)

Azure SDK

Use github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute and github.com/Azure/azure-sdk-for-go/sdk/monitor. Auth should use azidentity.NewDefaultAzureCredential() (respects az login, env vars, managed identity).

Happy to review PRs and help with architecture decisions — just need someone who can test against real Azure GPU VMs.