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).

README_CN.md

@@ -187,7 +187,7 @@ PYTHONPATH = "/path/to/artemis"
 
 你可以将 [`mcp_server/rules.md`](./mcp_server/rules.md) 挂载或复制到你的 AI IDE 规则配置中：
 * **Antigravity**：将 `rules.md` 内容添加至工作区规则（Workspace Rules）或全局规则设置中。
-* **Claude Code**：将 `rules.md` 内容复制或引入至项目根目录的 `CLAUDE.md` 文件中。
+* **Claude Code**：运行 `artemis mcp --install claude` 自动安装规则至 `~/.claude/rules/artemis.md`（只安装到单一位置——Claude Code 会同时加载 `~/.claude/CLAUDE.md` 与 `~/.claude/rules/*.md`，重复安装会浪费上下文）。
 * **Cursor**：将内容复制到 `.cursorrules` 文件或在 `.cursor/rules/artemis.mdc` 中创建新规则。
 * **Codex**：将内容添加至 `~/.codex/AGENTS.md`（或当前生效的 `AGENTS.override.md`）。
 * **Windsurf / OpenClaw**：将内容添加到工作区规则或全局 System Prompt 中。