fix(spec): match a merged label by its leading name on web too

The native desc rule accepts the label or the label at the head of an iOS
merged label; both web translators compared the whole string, so the same
selector matched natively and missed on web. The live-page parity test
caught it.

pkg/spec/src/web-runtime.ts

@@ -94,7 +94,10 @@ const KNOWN_KEY_TO_CSS: Record<string, (value: string) => string> = {
   // The native rule also accepts the local name after Android's "<package>:id/".
   // The DOM has no such prefix, so a plain starts-with is the same rule here.
   idPrefix: (v) => `[id^="${cssEscape(v)}"]`,
-  desc: (v) => `[aria-label="${cssEscape(v)}"]`,
+  // The native rule accepts the label itself or the label at the head of an
+  // iOS merged label ("account_card:7, Tim, $100"). `:is()` keeps that one
+  // compound piece, since a multi-key selector concatenates the parts.
+  desc: (v) => `:is([aria-label="${cssEscape(v)}"], [aria-label^="${cssEscape(v)}, "])`,
   descPrefix: (v) => `[aria-label^="${cssEscape(v)}"]`,
   // The native table aliases testTag onto resource-id, which the host DOM walk
   // fills from el.id, so the native path already accepts a testTag emitted as

pkg/spec/test/web-runtime.test.ts

@@ -342,6 +342,14 @@ test("selectorFromObject routes idPrefix to a starts-with id match", () => {
   });
 });
 
+// The native rule matches an iOS merged label ("account_card:7, Tim, $100") by
+// its leading name, and the web table has to mean the same thing by desc.
+test("selectorFromObject matches a merged label by its leading name", () => {
+  assert.deepEqual(selectorFromObject({ desc: "account_card" }), {
+    css: `:is([aria-label="account_card"], [aria-label^="account_card, "])`,
+  });
+});
+
 test("selectorFromString and selectorFromObject agree on descPrefix", () => {
   assert.deepEqual(selectorFromString("descPrefix:account:"), {
     css: `[aria-label^="account\\:"]`,