feat: extract in-process MCP action layer, concurrent task dispatch, and spawn/reconcile hardening

- Extract device action execution into artemis/mcp action layer:
  typed ActionResult, capability manifest with startup validation,
  AdbActuator as the single physical implementation, in-memory
  ActionSession (replaces stdio subprocess MCP in validator), and
  McpActionExecutor preserving the legacy executor contract.
  adb_server keeps its external stdio/SSE surface unchanged and now
  reuses the actuator implementation; import-time side effects moved
  into configure_stdio_mode().
- Capability-gated prompt assembly (prompt_assembly.py): tool enums and
  teaching segments render per available backend tools; full-set output
  is byte-identical to the previous static text (locked by tests).
- Admin console task queue: serial worker replaced by a per-device
  concurrent dispatcher (ARTEMIS_CONCURRENCY_MODE=global restores
  serial semantics), per-session cancellation, strict device binding on
  enqueue, unified stdio piping with tee to trace stdout.log, and
  shutdown cleanup of all active runs. Fix _pid_exists exception order
  so PermissionError is treated as alive.
- mcp_server reliability: spawn watchdog kills runners stuck before
  interpreter startup and releases device reservations; task state
  reconcile uses psutil liveness, prefers runner-reported pids, and
  adds a 45s startup grace to stop false failure reports on Windows;
  conversation_id is now optional end-to-end; explicit device_serial is
  validated at submission.
- CLI install now writes ~/.claude/rules/artemis.md for Claude Code and
  migrates/removes the legacy CLAUDE.md injection block; ~/.claude.json
  is never rewritten when it fails to parse.
- Tests: Windows-portable stdio lifecycle and path assertions; new
  suites for action layer, prompt assembly, spawn watchdog, and task
  reconcile (895 passed, 3 skipped).

artemis/mcp/actuators/base.py

@@ -0,0 +1,113 @@
+# 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.
+
+"""The actuator protocol: what any backend must look like to drive a device.
+
+An actuator answers exactly one question -- *how to perform a physical action* -- in
+the canonical 0-1000 normalized coordinate space. It knows nothing about LangGraph
+``State``, prompts, agents, screenshots-as-observations, or MCP. Pixel geometry (or a
+robot arm's motion planning) is a private detail behind this boundary.
+
+A backend advertises what it can do through :meth:`Actuator.capabilities` (names from
+``artemis.mcp.action_manifest.DEVICE_ACTIONS``) and may contribute tools nobody
+anticipated through :meth:`Actuator.extensions`. ``validate_actuator`` in the manifest
+enforces the contract at session start.
+
+Methods for actions a backend does not implement should simply not exist (or raise
+``NotImplementedError``); callers consult ``capabilities()`` first.
+"""
+
+from typing import Any, Protocol, runtime_checkable
+
+from artemis.mcp.action_manifest import ExtensionTool
+from artemis.mcp.action_types import ActionResult
+
+__all__ = ["Actuator"]
+
+
+@runtime_checkable
+class Actuator(Protocol):
+    """Protocol every actuator backend implements.
+
+    All coordinates are 0-1000 normalized. Every action coroutine returns an
+    :class:`ActionResult` and must not raise for device-level failures -- those are
+    reported through ``ok=False`` so a failed tap reaches the agent as an observation
+    rather than an exception.
+    """
+
+    def capabilities(self) -> frozenset[str]:
+        """Names from ``DEVICE_ACTIONS`` this backend implements."""
+        ...
+
+    def extensions(self) -> list[ExtensionTool]:
+        """Backend-specific tools unknown to the manifest."""
+        ...
+
+    # --- Required action -------------------------------------------------------------
+
+    async def click_sequence(
+        self, points: list[tuple[int, int]], delay_ms: int = 50
+    ) -> ActionResult: ...
+
+    # --- Optional actions ------------------------------------------------------------
+
+    async def click(
+        self, nx: int, ny: int, times: int = 1, delay_ms: int = 100
+    ) -> ActionResult: ...
+
+    async def long_press(self, nx: int, ny: int, duration_ms: int = 1000) -> ActionResult: ...
+
+    async def input_text(
+        self,
+        text: str,
+        target: tuple[int, int] | None = None,
+        clear_exist: bool = True,
+    ) -> ActionResult: ...
+
+    async def swipe(
+        self,
+        start: tuple[int, int],
+        end: tuple[int, int],
+        duration_ms: int = 800,
+    ) -> ActionResult: ...
+
+    async def press_key(self, key: str) -> ActionResult: ...
+
+    async def manage_app(self, action: str, app_name: str) -> ActionResult: ...
+
+    async def wait_for_delay(self, time_in_ms: int) -> ActionResult: ...
+
+    async def wait_for_text(
+        self, text: str, wait_state: str | None = None, timeout_ms: int | None = None
+    ) -> ActionResult: ...
+
+    async def open_link(self, url: str) -> ActionResult: ...
+
+    async def erase_one_char(self) -> ActionResult: ...
+
+    async def focus_and_clear_text(self, nx: int, ny: int) -> ActionResult: ...
+
+    # --- Internal observation primitives ---------------------------------------------
+
+    async def take_screenshot(self) -> str:
+        """Returns the current screen as a base64-encoded JPEG/PNG string."""
+        ...
+
+    async def get_ui_elements(self) -> Any:
+        """Returns the raw UI hierarchy elements as provided by the device."""
+        ...
+
+    async def get_screen_data(self) -> Any:
+        """Returns combined screen data (screenshot + elements + dimensions)."""
+        ...