perf(ios): early-exit text-entry readiness when the keyboard is visible

The XCUITest text-entry focus/readiness loops keyed their fast-exit on
focusedTextInput(), which is intentionally hardcoded to return nil on iOS (focus
predicates are stale there). As a result stabilizeTextInputBeforeTyping always
burned its full focusTimeout (0.4s) and waitForTextEntryReadiness burned its full
readinessTimeout (2.0s) in the normal case where the software keyboard appears —
~2.4s of dead wait before a single keystroke on every type/fill.

The software keyboard becoming visible is the reliable iOS readiness signal, so
both loops now return as soon as isKeyboardVisible() is true. The warmup-first-char
echo check and post-type verify/repair remain as drop safety nets.

Measured on iPhone 17 sim (Settings search field), median type time:
  25 chars:  3342ms -> 1379ms  (2.4x)
  52 chars:  3969ms -> 2190ms
  313 chars: 10.3s   -> 8.6s    (remainder is genuine per-char XCUITest typing)
Reliability unchanged: 64/65 trials exact (incl. a 50-word lorem ipsum, verified
by read-back + screenshot); the lone miss triggered the existing verify/repair.

Author: thymikee

ios-runner/AgentDeviceRunner/AgentDeviceRunnerUITests/RunnerTests+Interaction.swift

@@ -416,6 +416,12 @@ extension RunnerTests {
       if let focused = focusedTextInput(app: app) {
         return focused
       }
+      // focusedTextInput is intentionally nil on iOS, so the software keyboard becoming
+      // visible is the reliable readiness signal. Exit as soon as it is up instead of
+      // always burning the full focusTimeout.
+      if isKeyboardVisible(app: app) {
+        return latest
+      }
       sleepFor(TextEntryTiming.pollInterval)
     }
     return latest
@@ -878,6 +884,13 @@ extension RunnerTests {
           return focused
         }
       }
+      // The software keyboard being visible is the reliable readiness signal on iOS
+      // (focusedTextInput is intentionally nil there). Once it is up the field is accepting
+      // input, so return immediately rather than burning the full readinessTimeout — the
+      // warmup-first-char echo check and post-type verify/repair remain as drop safety nets.
+      if isKeyboardVisible(app: app) {
+        return latest
+      }
       sawSoftwareKeyboard = sawSoftwareKeyboard || keyboardElementExists(app: app)
       if !sawSoftwareKeyboard && Date() >= hardwareKeyboardFallback && latest != nil {
         return latest