refactor(domains): share target resolution and CDP error mapping

The ref-vs-x/y branch turned out to exist in one tool, not four; it is now
one helper with tests covering the half-specified-coordinate and stale-ref
cases. cdpCall folds the repeated cdp_error mapping at 24 active-session
call sites; target-scoped callOnTarget/callBrowser sites are left alone.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/domains/box.ts b/src/domains/box.ts
index e013f70..91f2f6a 100644
--- a/src/domains/box.ts
+++ b/src/domains/box.ts
@@ -1,6 +1,7 @@
 import type { BrowserClient } from "../client";
 import { type Result, err, ok } from "../util/result";
 import type { ToolErr } from "../util/tool";
+import { cdpCall } from "./cdp-call";
 
 export type Box = {
   readonly x: number;
@@ -34,8 +35,8 @@ export const boxOf = async (
   client: BrowserClient,
   backendNodeId: number,
 ): Promise<Result<Box, ToolErr>> => {
-  const r = await client.session().call("DOM.getBoxModel", { backendNodeId });
-  if (!r.success) return err({ kind: "cdp_error", message: r.error.message });
+  const r = await cdpCall(client, "DOM.getBoxModel", { backendNodeId });
+  if (!r.success) return r;
   const model = r.data.model;
   if (model.content.length < 8) {
     return err({ kind: "invalid_state", message: "DOM.getBoxModel returned an incomplete content quad" });