fix: change default OPENVIKING_ACCOUNT from root to default

- Change default OPENVIKING_ACCOUNT from 'root' to 'default'
- Add account and user config options to get_config_schema()
- Add session creation in initialize()
- Add reset_session() method
- Update docstring to reflect new default

This is a breaking change: existing users who relied on the 'root' account will need to either:
1. Set OPENVIKING_ACCOUNT=root in their environment, or
2. Migrate their data to the 'default' account

Future release will add support for OPENVIKING_ACCOUNT and OPENVIKING_USER in setup when API key is provided.

update desc for key setup

plugins/memory/openviking/__init__.py

@@ -10,7 +10,7 @@ lifecycle instead of read-only search endpoints.
 Config via environment variables (profile-scoped via each profile's .env):
   OPENVIKING_ENDPOINT  — Server URL (default: http://127.0.0.1:1933)
   OPENVIKING_API_KEY   — API key (required for authenticated servers)
-  OPENVIKING_ACCOUNT   — Tenant account (default: root)
+  OPENVIKING_ACCOUNT   — Tenant account (default: default)
   OPENVIKING_USER      — Tenant user (default: default)
 
 Capabilities:
@@ -83,7 +83,7 @@ class _VikingClient:
                  account: str = "", user: str = ""):
         self._endpoint = endpoint.rstrip("/")
         self._api_key = api_key
-        self._account = account or os.environ.get("OPENVIKING_ACCOUNT", "root")
+        self._account = account or os.environ.get("OPENVIKING_ACCOUNT", "default")
         self._user = user or os.environ.get("OPENVIKING_USER", "default")
         self._httpx = _get_httpx()
         if self._httpx is None:
@@ -282,10 +282,22 @@ class OpenVikingMemoryProvider(MemoryProvider):
             },
             {
                 "key": "api_key",
-                "description": "OpenViking API key",
+                "description": "OpenViking API key (leave blank for local dev mode)",
                 "secret": True,
                 "env_var": "OPENVIKING_API_KEY",
             },
+            {
+                "key": "account",
+                "description": "OpenViking tenant account ID (default, used when local mode, OPENVIKING_API_KEY is empty)",
+                "default": "default",
+                "env_var": "OPENVIKING_ACCOUNT",
+            },
+            {
+                "key": "user",
+                "description": "OpenViking user ID within the account (default, used when local mode, OPENVIKING_API_KEY is empty)",
+                "default": "default",
+                "env_var": "OPENVIKING_USER",
+            },
         ]
 
     def initialize(self, session_id: str, **kwargs) -> None: