Phase A1: bootstrap Python ci_orchestrator package

- pyproject.toml (hatchling) with ruff/mypy/pytest dev deps
- src/ci_orchestrator/: config, credentials, backends (Protocol + WorkstationVmrunBackend), transport (WinRM via pypsrp, SSH via paramiko)
- CLI entry point with PoC 'wait-ready' subcommand (Windows + Linux guests)
- tests/python/: 35 unit tests, 83% coverage, all backends/transport mocked
- gitea/workflows/lint.yml: new 'python' job (ruff + mypy --strict + pytest --cov-fail-under=70)
- config.example.toml + README setup section + .gitignore Python entries

Neutral VmBackend Protocol prepared for Phase C ESXi extension.
See plans/implementation-plan-A-B.md step A1.

src/ci_orchestrator/backends/protocol.py

@@ -0,0 +1,81 @@
+"""Neutral VM backend Protocol.
+
+Phase C hook: keep names hypervisor-agnostic. ``clone_linked``, ``start``,
+``stop``, ``delete``, ``get_ip``, ``list_snapshots`` map cleanly onto both
+``vmrun`` and pyVmomi (vSphere). Identifiers are opaque strings (a VMX path
+on Workstation, a managed object reference on ESXi).
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from enum import StrEnum
+from typing import Protocol
+
+
+class VmState(StrEnum):
+    """Coarse VM power state, normalised across backends."""
+
+    POWERED_OFF = "powered_off"
+    POWERED_ON = "powered_on"
+    SUSPENDED = "suspended"
+    UNKNOWN = "unknown"
+
+
+@dataclass(frozen=True)
+class VmHandle:
+    """Opaque reference to a VM managed by a backend.
+
+    ``identifier`` is backend-specific (a VMX path for Workstation, a
+    managed object reference for vSphere). Callers MUST treat it as opaque.
+    """
+
+    identifier: str
+    name: str | None = None
+
+
+class VmBackend(Protocol):
+    """Hypervisor-agnostic VM operations.
+
+    All methods raise :class:`~ci_orchestrator.backends.errors.BackendError`
+    on failure. Implementations are free to add backend-specific kwargs but
+    MUST honour the documented signature for the listed parameters.
+    """
+
+    def clone_linked(
+        self,
+        template: str,
+        snapshot: str,
+        name: str,
+        destination: str | None = None,
+    ) -> VmHandle:
+        """Create a linked clone of ``template`` at snapshot ``snapshot``."""
+        ...
+
+    def start(self, handle: VmHandle, headless: bool = True) -> None:
+        """Power on the VM."""
+        ...
+
+    def stop(self, handle: VmHandle, hard: bool = False) -> None:
+        """Power off the VM. ``hard=True`` requests a forced power-off."""
+        ...
+
+    def delete(self, handle: VmHandle) -> None:
+        """Remove the VM from inventory and delete its files."""
+        ...
+
+    def get_ip(self, handle: VmHandle, timeout: float = 0.0) -> str | None:
+        """Return the guest's primary IP, or ``None`` if not yet known."""
+        ...
+
+    def list_snapshots(self, handle: VmHandle) -> list[str]:
+        """Return snapshot names defined on ``handle``."""
+        ...
+
+    def is_running(self, handle: VmHandle) -> bool:
+        """Return ``True`` if the VM appears in the running-VM list.
+
+        Implementations MUST NOT rely on guest tools (e.g. ``vmrun
+        getGuestIPAddress``) for this check — see ``AGENTS.md`` error #10.
+        """
+        ...