feat: add agentic video analysis and clarify action results

Report device actions as dispatched and preserve full failure details. Route
Flash through McpActionExecutor and use ToolFailure across helper tools and
agent loops instead of inferring failure from response text.

Require model-provided descriptions for coordinate targets. Keep observed
element metadata separate from those descriptions in safety checks, visual
summaries, history, and frontend labels.

Add Gemini Interactions API video analysis with configurable processing mode,
chunk size, and timeouts. Centralize Google provider capabilities and token
usage normalization, and update google-genai to 2.22.0.

Preserve system instructions on follow-up interactions, replan pending chunks
when falling back to static processing, and reject unanswered native video
and audio segments instead of caching placeholder results. Keep helper-tool
failure status intact through history tools and committee calls.

Validation: 1,762 Python unit tests passed (3 skipped), 40 frontend formatter
tests passed, and the production UI build completed. Ruff lint, formatting,
the quality ratchet, and git diff checks passed.

tests/unit/agents/test_precondition_pixel_target.py

@@ -64,6 +64,10 @@ def test_coordinates_only_target_is_labelled_as_surface():
 
     first_text = messages[1].content[0]["text"]
     assert "Kind: coordinates only" in first_text
+    # No hit test runs any more: the block states that nothing was recorded, it
+    # does not claim the point was looked up in the UI hierarchy.
+    assert "no target metadata recorded" in first_text
+    assert "UI hierarchy" not in first_text
     assert "Label:" not in first_text
     assert "Resource ID:" not in first_text
     assert not any("Original Thinking" in t for t in _texts(messages))
@@ -77,13 +81,12 @@ def test_label_alone_counts_as_named_control():
     assert "Resource ID" not in text
 
 
-def test_unlabelled_hit_test_element_is_still_a_control():
+def test_unlabelled_indexed_element_is_still_a_control():
     item = {
         "action": "tap",
         "coordinates": [1001, 718],
         "target_class": "android.widget.ImageView",
         "target_bounds": [922, 655, 1080, 781],
-        "target_label_source": "hit_test",
     }
     text = pp._describe_target(item)
     assert "Kind: specific UI control" in text
@@ -92,9 +95,33 @@ def test_unlabelled_hit_test_element_is_still_a_control():
     assert "[922, 655, 1080, 781]" in text
 
 
+def test_described_coordinate_target_is_its_own_kind():
+    """The model's description is presented as its belief, not as observed metadata."""
+    item = {"action": "tap", "coordinates": [540, 400], "target_description": "play button"}
+    text = pp._describe_target(item)
+    assert "Kind: described target" in text
+    assert "Operator's description: play button" in text
+    assert "Kind: specific UI control" not in text
+    assert "Label:" not in text
+
+
+def test_observed_metadata_outranks_description():
+    item = {
+        "action": "tap",
+        "coordinates": [10, 10],
+        "target_text": "Submit",
+        "target_description": "ignored",
+    }
+    text = pp._describe_target(item)
+    assert "Kind: specific UI control" in text
+    assert "Label: Submit" in text
+    assert "described target" not in text
+
+
 def test_prompt_rules_are_keyed_on_target_kind():
     prompt = Path(pp.__file__).with_name("pixel_safety_net.md").read_text(encoding="utf-8")
     assert "`Kind: specific UI control`" in prompt
+    assert "`Kind: described target`" in prompt
     assert "`Kind: coordinates only`" in prompt
     assert "hidden" in prompt
     assert "Identify what appears under the red dot" in prompt