Delete extensions without implicit cleanup

[IlyaasK]

Summary

• delete extensions by canonical state ID and recorded project scope
• treat coded extension not_found as converged success
• recognize only the API's HTTP 400 resource_in_use dependency contract
• direct operators to remove durable browser-pool references
• preserve generic 400/404, project, and transport failures as diagnostics
• validate state before mutation and perform no force or runtime cleanup

Why this is v1 work

This is the pure Delete core needed before Framework Delete and complete resource registration.

Intentionally unsupported

• no Framework Delete adapter or resource registration
• no force delete, implicit pool mutation, or runtime cleanup
• no browser/session operation

Verification

gofmt -l cmd internal, go test -count=20 ./internal/resources/extension, extension race tests, full short tests, go vet ./..., go mod tidy -diff, and git diff --check all passed. Tests use a fake client and no network/container.

Acceptance status

No registered complete resource exists yet, so live acceptance testing is not applicable.

Remaining risk

Delete remains blocked while durable browser pools reference the extension. Terraform intentionally does not alter those dependencies implicitly.

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Note

Low Risk
New isolated delete helper and tests only; no Framework registration or live resource wiring yet, with explicit non-mutation of browser pools on dependency errors.

Overview
Adds the extension delete core (deleteExtension) that the Terraform resource will call later: it deletes by state id and project_id, validates state before any API call, and maps API outcomes to diagnostics.

Idempotent delete: coded not_found responses are treated as success via projectscope.IsNotFound. Dependency blocking: only HTTP 400 bodies with resource_in_use are recognized as “in use”; operators get a message to remove durable browser pool references, with no implicit pool or runtime cleanup.

Other failures (generic 400/404, transport, missing client) surface as normal delete errors. Unit tests cover scope/identity, not-found success, in-use messaging, error classification, and pre-call state validation.

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