Simplify apps/cli/ code

- config.ts: Convert arrow functions to function declarations
- api-client.ts: Extract duplicated RPCLink logic into buildClient helper
- format-error.ts: Add centralized ORPCError handling
- complete-login.ts: Remove redundant error handling (now in formatError)
- status.ts: Simplify formatRelativeTime, improve whitespace
- create.ts: Rename validRoles to VALID_ROLES, add as const, early return
- completions.ts: Derive Shell type from SUPPORTED_SHELLS array

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/cli/src/utils/format-error.ts

@@ -1,8 +1,14 @@
+import { ORPCError } from "@orpc/client";
+
 /**
  * Format an unknown error value into a string message.
- * Handles Error instances, strings, and other types safely.
+ * Handles ORPCError, Error instances, strings, and other types safely.
  */
 export function formatError(error: unknown): string {
+  if (error instanceof ORPCError) {
+    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions -- ORPCError.code is typed as any
+    return `[${error.code}] ${error.message}`;
+  }
   if (error instanceof Error) {
     return error.message;
   }