chore(ios-runner): delete the unreachable synthesized .continuous drag profile #2790

Purpose

The synthesized .continuous drag profile cannot run. The only daemon code that produces drag (packages/platform-apple/src/interactions.ts:343-355) is macOS-only and never sends synthesized. Every live call to the synthesized gesture API passes .fastSwipe or .controlledScroll.

Dead code, with paths under apple/runner/AgentDeviceRunner/AgentDeviceRunnerUITests/ and line references at 01328de411:

• RunnerSynthesizedGesture.m:120-141 (synthesizeContinuousDrag)
• RunnerSynthesizedGesture.m:414-432 (RunnerContinuousDragPointerPath)
• RunnerSynthesizedGesture.m:481-483 (RunnerSmoothstepProgress)
• the matching declarations in RunnerSynthesizedGesture.h:22-28, and the frame-count export
• the second if synthesized block in executeDragGesture (RunnerTests+CommandExecution.swift:2369-2391), and the synthesized: parameter

In total this is about 100 lines.

Required behavior

• Delete the code listed above. .fastSwipe and .controlledScroll stay byte-identical.
• Move the ADR 0013 / Two iOS drag synthesis strategies now coexist; document or reconcile them #1586 rationale comment (.m:420-422) to wherever it still applies, or delete it if it described only the continuous path.

Completion conditions

• grep -rn -i continuous apple/runner/AgentDeviceRunner/AgentDeviceRunnerUITests finds no drag-profile code.
• Run pnpm check:xctest-selection, build the runner, and run the runner unit tests on the macOS host lane (see docs/agents/testing.md for signing and permissions). Add or change tests under the existing #if AGENT_DEVICE_RUNNER_UNIT_TESTS guard. Do not keep a second list of test names.
• The iOS simulator smoke lane is green, including scroll and swipe.