fix: fall back to name lookup for UUID-shaped workspace names (#24340)

`namedWorkspace` in `cli/root.go` parsed workspace identifiers with
`uuid.Parse` first and returned immediately on success, even when no
workspace had that UUID as its actual ID. This caused 404 errors for any
workspace whose name was a valid 32-char hex string (dashless UUID).

- Add `codersdk.ResolveWorkspace`: tries UUID lookup first, falls back
to name lookup on 404. `NameValid` guard skips the fallback for standard
dashed UUIDs (36 chars > 32-char name limit).
- Export `codersdk.SplitWorkspaceIdentifier`, replacing the duplicate
`splitNamedWorkspace` in `cli/root.go` (uses `strings.Cut`).
- Delete `namedWorkspace` from `cli/root.go`; all 28 call sites now use
`client.ResolveWorkspace` directly.
- Delete `namedWorkspace` and `splitNameAndOwner` from
`codersdk/toolsdk/bash.go`; inline `client.ResolveWorkspace`.
- Simplify `GetWorkspace` tool handler to a single `ResolveWorkspace`
call.
- Unit tests via httptest mock cover UUID, name, owner/name, UUID-like
fallback, not-found, server error, transport error, and invalid
identifier paths.
- Integration tests in `cli/show_test.go` and `codersdk/toolsdk` for
workspaces with UUID-like names.

> Generated with Coder Agents

codersdk/toolsdk/bash.go

@@ -190,7 +190,7 @@ func findWorkspaceAndAgent(ctx context.Context, client *codersdk.Client, workspa
 	}
 
 	// Get workspace
-	workspace, err := namedWorkspace(ctx, client, workspaceName)
+	workspace, err := client.ResolveWorkspace(ctx, workspaceName)
 	if err != nil {
 		return codersdk.Workspace{}, codersdk.WorkspaceAgent{}, err
 	}
@@ -274,37 +274,6 @@ func getWorkspaceAgent(workspace codersdk.Workspace, agentName string) (codersdk
 	return codersdk.WorkspaceAgent{}, xerrors.Errorf("multiple agents found, please specify the agent name, available agents: %v", availableNames)
 }
 
-func splitNameAndOwner(identifier string) (name string, owner string) {
-	// Parse owner and name (workspace, task).
-	parts := strings.SplitN(identifier, "/", 2)
-
-	if len(parts) == 2 {
-		owner = parts[0]
-		name = parts[1]
-	} else {
-		owner = "me"
-		name = identifier
-	}
-
-	return name, owner
-}
-
-// namedWorkspace gets a workspace by owner/name or just name
-func namedWorkspace(ctx context.Context, client *codersdk.Client, identifier string) (codersdk.Workspace, error) {
-	workspaceName, owner := splitNameAndOwner(identifier)
-
-	// Handle -- separator format (convert to / format)
-	if strings.Contains(identifier, "--") && !strings.Contains(identifier, "/") {
-		dashParts := strings.SplitN(identifier, "--", 2)
-		if len(dashParts) == 2 {
-			owner = dashParts[0]
-			workspaceName = dashParts[1]
-		}
-	}
-
-	return client.WorkspaceByOwnerAndName(ctx, owner, workspaceName, codersdk.WorkspaceOptions{})
-}
-
 // executeCommandWithTimeout executes a command with timeout support
 func executeCommandWithTimeout(ctx context.Context, session *gossh.Session, command string) ([]byte, error) {
 	// Set up pipes to capture output