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/unit/services/dbapi/conftest.py

@@ -0,0 +1,43 @@
+# retoor <retoor@molodetz.nl>
+
+from datetime import datetime, timezone
+
+import pytest
+
+from devplacepy.database import get_table, purge, refresh_snapshot
+from devplacepy.utils import generate_uid
+
+
+@pytest.fixture(autouse=True)
+def _seed_dbapi_schema(local_db):
+    now = datetime.now(timezone.utc).isoformat()
+    users = get_table("users")
+    if "username" not in users.columns:
+        users.insert(
+            {
+                "uid": generate_uid(),
+                "username": "dbapi_seed",
+                "email": "seed@dbapi.test",
+                "role": "Member",
+                "xp": 0,
+                "level": 1,
+                "created_at": now,
+            }
+        )
+    bookmarks = get_table("bookmarks")
+    if "user_uid" not in bookmarks.columns:
+        seed = generate_uid()
+        bookmarks.insert(
+            {
+                "uid": seed,
+                "user_uid": "_seedcols",
+                "target_type": "post",
+                "target_uid": "_s",
+                "created_at": now,
+                "deleted_at": None,
+                "deleted_by": None,
+            }
+        )
+        purge("bookmarks", uid=seed)
+    refresh_snapshot()
+    yield