Fix linting issues: canonicalheader, embeddedstructfieldcheck, iotamixing, makezero, testableexamples, wastedassign, usetesting, tparallel, unconvert, intrange, iface

- canonicalheader: fix cacheTTL header value to canonical form
- embeddedstructfieldcheck: move embedded fields before regular fields in 4 structs
- iotamixing: split const blocks mixing iota with non-iota constants
- makezero: use make([]T, 0, n) instead of make([]T, n) before appending
- testableexamples: add missing Output: comment to ExampleOption_UnwrapOrZero
- wastedassign: remove wasted initial assignments in 4 locations
- usetesting: replace os.MkdirTemp/os.Setenv with t.TempDir/t.Setenv in tests
- tparallel: add t.Parallel() to 8 top-level test functions
- unconvert: remove 16 unnecessary type conversions
- intrange: convert 3 for loops to use integer range syntax
- iface: consolidate identical EditPrompter and Prompt interfaces via type alias

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

internal/codespaces/api/api.go

@@ -952,7 +952,6 @@ func (a *API) startCreate(ctx context.Context, params *CreateCodespaceParams) (*
 		resp.Body = io.NopCloser(bodyCopy)
 
 		return nil, api.HandleHTTPError(resp)
-
 	} else if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
 		return nil, api.HandleHTTPError(resp)
 	}