refactor: one door from a tool to the browser

Four routes coexisted: cdpCall, a raw client.session().call, a session
held in a local and called directly, and client.evaluateJs — and five
files mixed two or three of them. The CdpError-to-ToolErr mapping was
hand-copied at nine sites, plus a private copy in isolated-tab.ts.

domains/cdp-call.ts now owns all of it: cdpErrToToolErr, cdpCall,
cdpCallOnTarget, cdpCallBrowser, evalJs. Every other file under
src/domains goes through them, which also removes a pile of
`if (!r.success) return err({ kind: "cdp_error", ... })` boilerplate in
favour of returning the failed Result as-is.

Two scanner rules keep it that way, scoped to src/domains/ so the layer
that legitimately owns the session — cdp/ and client.ts — is unaffected.
Scoping is new to the rule model; without it the rules fired on the
transport itself.

One deliberate behaviour change: a CDP timeout now surfaces as
kind "timeout" rather than "cdp_error". isolated-tab.ts already did this
and the other 13 sites flattened it; the shared mapper uses the honest
label rather than preserving the mislabel.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/src/domains/tabs.ts b/src/domains/tabs.ts
index f932fbf..a2c3831 100644
--- a/src/domains/tabs.ts
+++ b/src/domains/tabs.ts
@@ -1,6 +1,7 @@
 import { Type } from "typebox";
 import { type Result, err, ok } from "../util/result";
 import { defineBrowserTool, type ToolErr, type ToolOk } from "../util/tool";
+import { cdpCallBrowser } from "./cdp-call";
 
 const ListTabsArgs = Type.Object({
   includeInternal: Type.Optional(Type.Boolean({ default: true, description: "Include chrome:// pages" })),
@@ -55,8 +56,8 @@ export const currentTabTool = defineBrowserTool({
   async handler(_a, { client }): Promise<Result<ToolOk, ToolErr>> {
     const cur = client.current();
     if (!cur) return err({ kind: "invalid_state", message: "No tab attached." });
-    const ti = await client.session().callBrowser("Target.getTargetInfo", { targetId: cur.targetId });
-    if (!ti.success) return err({ kind: "cdp_error", message: ti.error.message });
+    const ti = await cdpCallBrowser(client, "Target.getTargetInfo", { targetId: cur.targetId });
+    if (!ti.success) return ti;
     const info = ti.data.targetInfo;
     const owned = client.owns(info.targetId);
     return ok({