refactor: clean up legacy code, rename hopper to entity_extractor, and add third-party notices

- Add NOTICE file and README license references for mobile-use and finalrun-agent
- Add derivative attribution headers to 17 files derived from mobile-use
- Rename hopper agent to entity_extractor across prompts, tools, and configs
- Remove obsolete adb_tunnel, ApiBaseUrl, and legacy CLI utility scripts
- Replace legacy examples with native Artemis diagnostic and workflow examples
- Update unit and tool tests to validate entity_extractor and SDK builders

tests/unit/sdk/test_exceptions.py

@@ -0,0 +1,63 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests validating Artemis SDK exception hierarchy and diagnostics."""
+
+from artemis.sdk.types.exceptions import (
+    AgentError,
+    AgentNotInitializedError,
+    AgentProfileNotFoundError,
+    AgentTaskRequestError,
+    ArtemisError,
+    DeviceError,
+    DeviceNotFoundError,
+    ExecutableNotFoundError,
+    ServerError,
+    ServerStartupError,
+)
+
+
+def test_exception_hierarchy():
+    """Verify all custom exceptions inherit properly from ArtemisError."""
+    assert issubclass(DeviceError, ArtemisError)
+    assert issubclass(DeviceNotFoundError, DeviceError)
+    assert issubclass(ServerError, ArtemisError)
+    assert issubclass(ServerStartupError, ServerError)
+    assert issubclass(AgentError, ArtemisError)
+    assert issubclass(AgentNotInitializedError, AgentError)
+    assert issubclass(AgentTaskRequestError, AgentError)
+    assert issubclass(AgentProfileNotFoundError, AgentTaskRequestError)
+    assert issubclass(ExecutableNotFoundError, ArtemisError)
+
+
+def test_executable_not_found_error_adb_guidance():
+    """Verify executable error formats download instructions for known tools."""
+    err = ExecutableNotFoundError("adb")
+    assert "adb" in str(err)
+    assert "developer.android.com" in str(err)
+    assert err.executable_name == "adb"
+
+
+def test_server_startup_error_formatting():
+    """Verify server startup error encapsulates service identifier."""
+    err = ServerStartupError(server_name="mcp_daemon")
+    assert "mcp_daemon" in str(err)
+    assert err.server_name == "mcp_daemon"
+
+
+def test_agent_profile_not_found_error():
+    """Verify profile error retains profile name."""
+    err = AgentProfileNotFoundError("nonexistent_profile")
+    assert "nonexistent_profile" in str(err)
+    assert err.profile_name == "nonexistent_profile"