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_fixture_validation.py

@@ -79,12 +79,14 @@ async def main(executable):
                     "by": "page",
                     "x": 400,
                     "y": 470,
+                    "capture_id": pixel.structuredContent["observation"]["capture_id"],
                 },
             )
             if scrolled.isError:
                 assert (
                     scrolled.structuredContent["artemis"]["execution"] == "not_started"
                 ), scrolled
+                state = await session.call("get_window_state", target)
                 scrolled = await session.call(
                     "scroll",
                     {
@@ -94,6 +96,7 @@ async def main(executable):
                         "by": "page",
                         "x": 400,
                         "y": 470,
+                        "capture_id": state.structuredContent["capture_id"],
                         "delivery_mode": "foreground",
                     },
                 )