fix(adapter): close final foundation review

harness/tests/test_config_legacy_compat.py

@@ -1,10 +1,14 @@
 import json
+import os
+import subprocess
+from pathlib import Path
 
 import pytest
 from typer.testing import CliRunner
 
 from tht.cli import app
 from tht.config import load_config
+from tht.adapters.factory import build_vector_store
 
 
 def _write_old_workspace(tmp_path):
@@ -103,3 +107,42 @@ def test_legacy_warning_does_not_contaminate_cli_json(tmp_path):
     assert "DEPRECATION" not in result.stdout
     assert result.stderr == ""
     assert len(warnings) == 1
+
+
+def test_legacy_cli_subprocess_warns_once_on_stderr_and_keeps_json_stdout(tmp_path):
+    workspace = _write_old_workspace(tmp_path)
+    result = subprocess.run(
+        [
+            str(Path(__file__).parents[1] / ".venv" / "bin" / "tht"),
+            "session",
+            "list",
+            "--json",
+            "-c",
+            str(workspace),
+        ],
+        cwd=tmp_path,
+        env={**os.environ, "PYTHONWARNINGS": "default"},
+        text=True,
+        capture_output=True,
+        check=False,
+    )
+
+    assert result.returncode == 0
+    json.loads(result.stdout)
+    assert "DEPRECATION" not in result.stdout
+    assert result.stderr.count("DEPRECATION") == 1
+
+
+def test_legacy_writer_only_vector_config_builds_for_targeted_writes(tmp_path):
+    workspace = _write_old_workspace(tmp_path)
+    content = workspace.read_text().replace(
+        "vector_rest:\n  base_url: https://vectors.example.test/\n  api_key: vector-reader\n",
+        "",
+    )
+    workspace.write_text(content)
+
+    with pytest.warns(FutureWarning):
+        cfg = load_config(workspace)
+    store = build_vector_store(cfg, require_write=True)
+    assert store.capabilities.search is False
+    assert store.capabilities.upsert is True