[hotfix] orchestrator: strip /app/.venv pin from workspace uv env

_uv_subprocess_env inherited the image-baked VIRTUAL_ENV=/app/.venv (the
orchestrator gateway venv), so every workspace uv call (uv sync --extra dev
provisioning, dep-update uv lock, toolchain detect) warned on the NAS:
'VIRTUAL_ENV=/app/.venv does not match the project environment path .venv
and will be ignored'. uv already used the clone .venv via cwd discovery, so
stripping VIRTUAL_ENV + UV_PROJECT_ENVIRONMENT is noise-only and keeps
per-project isolation (each clone discovers its OWN .venv). Companion to the
agent-image VIRTUAL_ENV removal (7be10057); ships on orchestrator redeploy.

Verified: test_uv_subprocess_env_strips_app_venv_pin + the 3 clone-venv
resolution tests; ruff/mypy clean.

tests/unit/services/test_workspace_uv_resolves_clone_venv.py

@@ -19,7 +19,7 @@ from pathlib import Path
 from unittest.mock import MagicMock, patch
 
 import pytest
-from roboco.services.workspace import WorkspaceService
+from roboco.services.workspace import WorkspaceService, _uv_subprocess_env
 
 pytestmark = pytest.mark.skipif(
     shutil.which("uv") is None, reason="uv CLI not installed"
@@ -132,3 +132,19 @@ async def test_clone_root_stays_on_default_after_worktree_add(clone: Path) -> No
     )
     assert _git(wt1, "branch", "--show-current").strip() == "feature/a"
     assert _git(wt2, "branch", "--show-current").strip() == "feature/b"
+
+
+def test_uv_subprocess_env_strips_app_venv_pin(tmp_path, monkeypatch):
+    # The orchestrator runs uv with cwd= a workspace clone, so the env it
+    # passes must NOT carry the image-baked VIRTUAL_ENV=/app/.venv (or the
+    # UV_PROJECT_ENVIRONMENT MCP pin) — uv would warn "does not match project
+    # .venv, will be ignored" on every sync. uv discovers the clone .venv via
+    # cwd either way; stripping is noise-only and keeps per-project isolation.
+    clone = tmp_path / "clone"
+    clone.mkdir()
+    monkeypatch.setenv("VIRTUAL_ENV", "/app/.venv")
+    monkeypatch.setenv("UV_PROJECT_ENVIRONMENT", "/app/.venv")
+    env = _uv_subprocess_env(clone)
+    assert "VIRTUAL_ENV" not in env
+    assert "UV_PROJECT_ENVIRONMENT" not in env
+    assert env["UV_PYTHON_INSTALL_DIR"] == str(clone / ".uv-python")