After conflict resolution from rebase, some imports were accidentally
removed and the CORS middleware function was eliminated but still
referenced by tests. This commit:
- Adds fmt import to api/rest/keys.go (used for error messages)
- Adds gorilla/mux import to cmd/server/main.go (used for router type)
- Restores newCORSMiddleware function to api/rest/router.go for test compatibility
- Formats code with gofmt
igodwin