fix: properly return final state for wait commands

[darwich6]

Behavior changes:

• branch create --wait now prints the final MySQL or PostgreSQL branch.
• database create --wait now prints the final ready database.
• keyspace create --wait now prints the final ready keyspace.
• deploy-request deploy --wait now prints the final deploy request.
• branch switch --wait ignores the returned branch because it does not print a resource.
• Poll intervals and timeouts remain unchanged.

Tests added:

• MySQL branch creation
• PostgreSQL branch creation
• Database creation
• Keyspace creation
• Deploy-request deployment

Validation:

• Focused tests passed.
• go vet passed.
• All four paths passed live tests in benchmarks.
• Test resources were deleted.