feat: add admin/internal database API with CRUD, read-only query, and natural-language SQL endpoints

Add a new `/dbapi` router package providing a generic database API over `dataset`, restricted to admin sessions, admin API keys, and the internal gateway key. Includes:

- `tables.py`: list all tables and inspect table schemas
- `crud.py`: full CRUD operations (GET, POST, PATCH, DELETE) with soft-delete awareness, born-live inserts, `?include_deleted`, `.../restore`, and `?hard=true` purge
- `query.py`: validated read-only SELECT execution via sqlglot parsing, classification, and EXPLAIN dry-run; async query jobs with WebSocket streaming via `DbApiJobService`
- `nl.py`: natural-language-to-SQL conversion using the platform AI gateway with re-prompting until validation passes

Also register `DbApiJobService` and `PubSubService` in the service manager, add `DBAPI_DIR` to config data paths, and force cleartext `http://` connections to HTTP/1.1 in `curl_transport` to fix large request failures against uvicorn's HTTP/1.1-only internal gateway.

tests/api/dbapi/nl.py

@@ -0,0 +1,37 @@
+# retoor <retoor@molodetz.nl>
+
+
+def test_nl_requires_auth(client):
+    assert (
+        client.post("/dbapi/nl", json={"question": "x", "table": "users"}).status_code
+        == 403
+    )
+
+
+def test_nl_missing_fields_is_400(client, auth):
+    assert client.post("/dbapi/nl", json={"question": "x"}, headers=auth).status_code == 400
+
+
+def test_nl_denied_table_is_404(client, auth):
+    response = client.post(
+        "/dbapi/nl", json={"question": "x", "table": "sessions"}, headers=auth
+    )
+    assert response.status_code == 404
+
+
+def test_nl_is_graceful_when_gateway_fails(client, auth, monkeypatch):
+    async def _boom(*args, **kwargs):
+        raise RuntimeError("gateway down")
+
+    monkeypatch.setattr(
+        "devplacepy.services.dbapi.nl2sql._complete", _boom
+    )
+    response = client.post(
+        "/dbapi/nl",
+        json={"question": "all administrators", "table": "users"},
+        headers=auth,
+    )
+    assert response.status_code == 200
+    body = response.json()
+    assert body["valid"] is False
+    assert body["error"]