fix: bind Cua pixel actions to current screenshot geometry

Correct native scroll scaling, reject stale or out-of-bounds pixel targets, and scope DPI awareness to geometry reads. Package adapter 0.36.0+artemis.3 and document the high-effort cross-device verification.

Validation: Go tests and vet, packaged MCP schema and handshake, Python checks, and user-run high-effort task completed with a passed verdict and explicit coverage limits.

tests/cua_browser_smoke.py

@@ -54,7 +54,7 @@ async def model_task(base, pid, url, output, events, traces, model):
                     {
                         "id": "cua-driver",
                         "profile": "benchmark",
-                        "version": "0.36.0+artemis.2",
+                        "version": "0.36.0+artemis.3",
                     }
                 ],
                 "model": model,
@@ -353,6 +353,7 @@ async def run(
                             "by": "page",
                             "x": source["width"] // 2,
                             "y": source["height"] // 2,
+                            "capture_id": state["capture_id"],
                             "delivery_mode": "foreground",
                         },
                     )