feat: add data vault store with key-value operations

- DataVaultStore class with sync get/set/delete/list_keys methods
- AsyncDataVaultStore class with async variants
- Export both from models package

sdks/implementations/python/src/stack_auth/models/__init__.py

@@ -1,5 +1,6 @@
 """Stack Auth data models -- re-exports all model classes."""
 
+from stack_auth.models.data_vault import AsyncDataVaultStore, DataVaultStore
 from stack_auth.models.api_keys import (
     ApiKey,
     TeamApiKey,
@@ -19,6 +20,8 @@ from stack_auth.models.teams import ServerTeam, Team, TeamInvitation, TeamMember
 from stack_auth.models.users import BaseUser, ServerUser
 
 __all__ = [
+    "DataVaultStore",
+    "AsyncDataVaultStore",
     "BaseUser",
     "ServerUser",
     "Team",

sdks/implementations/python/src/stack_auth/models/data_vault.py

@@ -0,0 +1,87 @@
+"""Data vault store classes for server-side key-value storage."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from stack_auth.errors import NotFoundError
+
+
+class DataVaultStore:
+    """Synchronous data vault store -- a server-side key-value store.
+
+    Obtained via ``StackServerApp.get_data_vault_store(store_id)``.
+    """
+
+    def __init__(self, store_id: str, *, _client: Any) -> None:
+        self.id = store_id
+        self._client = _client
+        self._base_path = f"/data-vault/stores/{store_id}/items"
+
+    def get(self, key: str) -> str | None:
+        """Get the value for a key, or ``None`` if not found."""
+        try:
+            data = self._client.request("GET", f"{self._base_path}/{key}")
+        except NotFoundError:
+            return None
+        if data is None:
+            return None
+        return data.get("value") if isinstance(data, dict) else data
+
+    def set(self, key: str, value: str) -> None:
+        """Set or update the value for a key."""
+        self._client.request("PUT", f"{self._base_path}/{key}", body={"value": value})
+
+    def delete(self, key: str) -> None:
+        """Delete a key-value pair. No error if key doesn't exist."""
+        self._client.request("DELETE", f"{self._base_path}/{key}")
+
+    def list_keys(self) -> list[str]:
+        """Return all keys in the store."""
+        data = self._client.request("GET", self._base_path)
+        if data is None:
+            return []
+        # Response may be {"items": [...]} or a list directly
+        if isinstance(data, dict):
+            return data.get("items", [])
+        return data
+
+
+class AsyncDataVaultStore:
+    """Asynchronous data vault store -- a server-side key-value store.
+
+    Obtained via ``AsyncStackServerApp.get_data_vault_store(store_id)``.
+    """
+
+    def __init__(self, store_id: str, *, _client: Any) -> None:
+        self.id = store_id
+        self._client = _client
+        self._base_path = f"/data-vault/stores/{store_id}/items"
+
+    async def get(self, key: str) -> str | None:
+        """Get the value for a key, or ``None`` if not found."""
+        try:
+            data = await self._client.request("GET", f"{self._base_path}/{key}")
+        except NotFoundError:
+            return None
+        if data is None:
+            return None
+        return data.get("value") if isinstance(data, dict) else data
+
+    async def set(self, key: str, value: str) -> None:
+        """Set or update the value for a key."""
+        await self._client.request("PUT", f"{self._base_path}/{key}", body={"value": value})
+
+    async def delete(self, key: str) -> None:
+        """Delete a key-value pair. No error if key doesn't exist."""
+        await self._client.request("DELETE", f"{self._base_path}/{key}")
+
+    async def list_keys(self) -> list[str]:
+        """Return all keys in the store."""
+        data = await self._client.request("GET", self._base_path)
+        if data is None:
+            return []
+        # Response may be {"items": [...]} or a list directly
+        if isinstance(data, dict):
+            return data.get("items", [])
+        return data