Align studio registry consumers with toolhive's v0.1 registry surface

Summary

The toolhive backend is removing the legacy registry format and aligning its registry API with the v0.1 surface that stacklok/toolhive-registry-server exposes. Studio needs to follow.

Phase 1 — Remove registry_legacy_format handling

Once the BE stops emitting registry_legacy_format (stacklok/toolhive#5278), the corresponding FE branches are dead code.

Files:

• renderer/src/common/components/settings/registry/registry-errors-message.ts — REGISTRY_LEGACY_FORMAT_CODE, isRegistryLegacyFormatError, legacy-format toast
• renderer/src/common/components/error/registry-error.tsx — isLegacyFormat branch
• Corresponding tests

Blocked on: stacklok/toolhive#5278

Phase 2 — Switch to v0.1 API and retype RegistryItem

Toolhive is removing /api/v1beta/registry/{name}/servers and aligning its v0.1 surface with toolhive-registry-server's swagger (stacklok/toolhive#5279). Studio needs to:

• Switch from /api/v1beta/registry/{name}/servers to the v0.1 endpoints — same pattern studio already uses for skills.
• Adopt the per-version sub-resources (/servers/{serverName}/versions, /versions/{version}) as they replace /versions/latest.
• Retype RegistryItem from RegistryImageMetadata | RegistryRemoteServerMetadata to the upstream MCP shape.
• Regenerate common/api/generated/ against the new OpenAPI spec.

Files (~15+): everything in renderer/src/features/registry-servers/ and renderer/src/features/mcp-servers/ that imports the legacy types, plus common/api/registry-types.ts.

Blocked on: stacklok/toolhive#5279

References

• BE phase 1: stacklok/toolhive#5278
• BE phase 2: stacklok/toolhive#5279
• Surface reference: stacklok/toolhive-registry-server docs/thv-registry-api/swagger.yaml
• Landed: stacklok/toolhive-catalog#1215, stacklok/toolhive-core#105, stacklok/toolhive#5273

Start with docs/thv-registry-api/swagger.yaml and the changes in stacklok/toolhive#5278 and #5279, then inspect common/api/registry-types.ts and the registry consumer files under renderer/src/features/registry-servers/ and renderer/src/features/mcp-servers/. Regenerate common/api/generated/ and update the corresponding registry error tests; done means Studio no longer handles the legacy format and consumes the v0.1 endpoints and types.