refactor: consolidate duplicate utility functions (#12439)

* refactor: consolidate duplicate utility functions

- Add escapeRegExp to src/utils.ts and remove 10 local duplicates
- Rename bash-tools clampNumber to clampWithDefault (different signature)
- Centralize formatError calls to use formatErrorMessage from infra/errors.ts
- Re-export formatErrorMessage from cli/cli-utils.ts to preserve API

* refactor: consolidate remaining escapeRegExp duplicates

* refactor: consolidate sleep, stripAnsi, and clamp duplicates

src/gateway/probe.ts

@@ -1,5 +1,6 @@
 import { randomUUID } from "node:crypto";
 import type { SystemPresence } from "../infra/system-presence.js";
+import { formatErrorMessage } from "../infra/errors.js";
 import { GATEWAY_CLIENT_MODES, GATEWAY_CLIENT_NAMES } from "../utils/message-channel.js";
 import { GatewayClient } from "./client.js";
 
@@ -26,13 +27,6 @@ export type GatewayProbeResult = {
   configSnapshot: unknown;
 };
 
-function formatError(err: unknown): string {
-  if (err instanceof Error) {
-    return err.message;
-  }
-  return String(err);
-}
-
 export async function probeGateway(opts: {
   url: string;
   auth?: GatewayProbeAuth;
@@ -65,7 +59,7 @@ export async function probeGateway(opts: {
       mode: GATEWAY_CLIENT_MODES.PROBE,
       instanceId,
       onConnectError: (err) => {
-        connectError = formatError(err);
+        connectError = formatErrorMessage(err);
       },
       onClose: (code, reason) => {
         close = { code, reason };
@@ -93,7 +87,7 @@ export async function probeGateway(opts: {
           settle({
             ok: false,
             connectLatencyMs,
-            error: formatError(err),
+            error: formatErrorMessage(err),
             close,
             health: null,
             status: null,