feat(gcp)!: withdraw DiskAsyncReplication until the agent can resolve a reference at plan time

[naxty]

Why

GCP::Compute::DiskAsyncReplication cannot pass conformance in any shape the plugin can take, and the reason is agent-side. It never shipped in a stable release (0.1.13-dev.1 / -dev.2 only), so withdrawing it costs no released surface, while keeping it costs a permanently red nightly on a defect that is not the plugin's to fix.

Its two properties are the disks the pair joins. Both are immutable, and both are declared as references to the disk resources, because that is how a forma names another resource:

primaryDisk = primary.res.selfLink
secondaryDisk = secondary.res.selfLink

An extracted forma writes such a reference unresolved, so the re-apply compares a $ref with no $value against the URL sitting in state, on a createOnly path, and plans a replacement of the pair already in place:

[Extract] Re-applying the extracted forma should be a zero-operation apply, but
the agent plans changes: delete plugin-sdk-test-disk-async-replication;
create plugin-sdk-test-disk-async-replication

The bind

run	plugin shape	CRUD	discovery
33145336853	writeOnly, Read reports the pair	❌ extract	–
33154860464	createOnly only, Read reports the pair	❌ extract	–
33153366449	writeOnly, Read reports {}	✅ 8/8	❌ discover
33155568420	writeOnly, Read reports nothing	✅ 8/8	❌ discover

All four against formae main. Suppressing the comparison fixes the lifecycle and makes the pair undiscoverable — the agent validates required fields on a resource it persists, and a writeOnly field is never returned by a Read:

Validation of required fields failed error="resource projects/…/asyncReplication/… of type
GCP::Compute::DiskAsyncReplication is missing required fields: [primaryDisk secondaryDisk]"

Reporting the pair keeps discovery and brings the replacement back. CI runs both phases, so neither half is a green build.

What this PR does

• Removes the provisioner, its unit tests, the schema module, the conformance case, the type constant and the README row.
• Carries the formae_branch input for debug-conformance over from the work branch — independent of the type, and without it a debug run installs the released formae and cannot reproduce a nightly-only failure at all.

go build ./..., go test ./... (203 tests, 43 packages) and pkl eval formae-plugin.pkl all green.

Where the work went

Draft PR #166 on naxty/fixAsyncDisk keeps the provisioner, the schema, the test case and the full analysis, including the two agent-side asks. It re-adds the type when the agent side lands.