feat(azure): Chaos Studio experiments (Microsoft.Chaos)

[NitinKumar004]

Summary

Adds a greenfield ARM control-plane emulation of Azure Chaos Studio experiments (Microsoft.Chaos/experiments), the primary parity target for Terraform's azurerm_chaos_studio_experiment. Control plane only — no faults are injected (this is unrelated to CloudEmu's features/chaos fault-injection engine).

Operations: CreateOrUpdate (PUT), Get, Delete, List by RG, List by subscription, Update (PATCH). Synchronous completion with provisioningState=Succeeded. Status codes 201/200/200-then-204/404.

Design

• Explicit top-level identity (echo_properties cannot reach top-level fields): type plus service-minted principalId/tenantId for SystemAssigned, and minted principalId/clientId per UserAssigned id. Minted once from a deterministic seed (idgen.SyntheticGUID), stored, and stable across every GET/PATCH and snapshot/restore.
• selectors / steps carried verbatim as raw JSON (json.RawMessage passthrough) so the deeply-nested branch/actions blocks — including the type:"List" and type:"continuous" discriminators Terraform's typed unmarshal requires — round-trip byte-for-byte and cannot drift. Bare creates default both to a valid [].
• provisioningState modeled explicitly under properties.
• PATCH merges only provided fields; location is immutable; resource-level tag update is a REPLACE.
• Resource-group delete cascades into experiments (purge).
• Resource-graph + discovery wired additively with unique keys: ServiceChaosStudio/TypeChaosExperiment, plus BOTH forward (microsoft.chaos/experiments -> {chaosstudio, Experiment}) and inverse (chaosstudio/Experiment -> microsoft.chaos/experiments) type-map entries.

E2E (raw ARM against cloudemu serve, api-version 2023-11-01)

• PUT create -> 201, provisioningState=Succeeded, identity ids minted, selectors/steps echoed verbatim.
• GET x2 -> byte-identical.
• PATCH tags -> 200, tags replaced, identity + selectors + steps all stable (no drift).
• DELETE -> 200, DELETE again -> 204, GET -> 404.
• Resource Graph where type =~ "microsoft.chaos/experiments" -> 1 row, inverse type emitted correctly.

Gates

go build ./..., full go vet ./..., gofmt clean, golangci-lint on new packages = 0 issues, go test -race on new packages, full go test of server/azure/... + providers/azure/... + services/resourcediscovery/... + server/azure/resourcegraph/... (128 pkgs), persist/... incl. completeness, root ., and go generate idempotency — all green.

Deferred

The nested targets/capabilities resource types (Microsoft.Chaos/targets, under other resources) are separate resource types and out of scope for this experiments-focused build.