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.md

@@ -185,7 +185,7 @@ To ensure your AI coding assistant acts with the rigor of a senior mobile test e
 
 You can mount or copy [`mcp_server/rules.md`](./mcp_server/rules.md) into your AI IDE's rule configuration:
 * **Antigravity**: Add the contents of `rules.md` to your Workspace Rules, Global Rules settings, or agent instructions.
-* **Claude Code**: Copy or include the contents of `rules.md` in your project's `CLAUDE.md` file.
+* **Claude Code**: Run `artemis mcp --install claude` to install the rules to `~/.claude/rules/artemis.md` (install to exactly one location — Claude Code loads both `~/.claude/CLAUDE.md` and `~/.claude/rules/*.md`, so duplicating the rules wastes context).
 * **Cursor**: Copy the contents into `.cursorrules` or create a rule file at `.cursor/rules/artemis.mdc`.
 * **Codex**: Add the contents to `~/.codex/AGENTS.md` (or the active `AGENTS.override.md`).
 * **Windsurf / OpenClaw**: Add the rules to your workspace rules or global system prompts.