feat(plugins): add source-aware evidence and recording timelines

artemis/agents/validator/execution_loop.py

@@ -426,6 +426,7 @@ async def run_validation_loop(node, state: State) -> dict:
     incident: dict | None = None
     success = False
     index = 0
+    step_pre_image_valid = True
 
     while actions_to_execute:
         action_item = actions_to_execute.pop(0)
@@ -450,8 +451,16 @@ async def run_validation_loop(node, state: State) -> dict:
             post_image_name = None
             plugin_action = bool(outcome.action_item.get("plugin_id"))
             mixed_plugin_action = (
-                plugin_action and getattr(ctx, "execution_target", "android") == "mixed"
+                plugin_action and getattr(ctx, "execution_target", "android") != "computer"
             )
+            if (
+                plugin_action
+                and not mixed_plugin_action
+                and not outcome.action_item.get("pre_image_valid", False)
+            ):
+                # The turn began on another window/geometry. Keep that observation
+                # out of the step's before/after evidence pair and archive exports.
+                step_pre_image_valid = False
             if outcome.post_screenshot_b64 and not mixed_plugin_action:
                 post_image_name = _absorb_post_screenshot(ctx, state, outcome.post_screenshot_b64)
                 last_screenshot_b64 = outcome.post_screenshot_b64
@@ -498,6 +507,8 @@ async def run_validation_loop(node, state: State) -> dict:
         "burst": burst,
         "incident": incident,
     }
+    if not step_pre_image_valid:
+        report["pre_image_valid"] = False
 
     # Determine if a distinct post-action screenshot was captured
     distinct_post_image_name = (