fix: store configs (#2593)

# What does this PR do?
https://github.com/meta-llama/llama-stack/pull/2490 broke postgres_demo,
as the config expected a str but the value was converted to int.

This PR:
1. Updates the type of port in sqlstore to be int
2. template generation uses `dict` instead of `StackRunConfig` so as to
avoid failing pydantic typechecks.
3. Adds `replace_env_vars` to StackRunConfig instantiation in
`configure.py` (not sure why this wasn't needed before).

## Test Plan
`llama stack build --template postgres_demo --image-type conda --run`

llama_stack/providers/utils/sqlstore/sqlstore.py

@@ -30,8 +30,8 @@ class SqlAlchemySqlStoreConfig(BaseModel):
     def engine_str(self) -> str: ...
 
     # TODO: move this when we have a better way to specify dependencies with internal APIs
-    @property
-    def pip_packages(self) -> list[str]:
+    @classmethod
+    def pip_packages(cls) -> list[str]:
         return ["sqlalchemy[asyncio]"]
 
 
@@ -48,20 +48,20 @@ class SqliteSqlStoreConfig(SqlAlchemySqlStoreConfig):
 
     @classmethod
     def sample_run_config(cls, __distro_dir__: str, db_name: str = "sqlstore.db"):
-        return cls(
-            type="sqlite",
-            db_path="${env.SQLITE_STORE_DIR:=" + __distro_dir__ + "}/" + db_name,
-        )
+        return {
+            "type": "sqlite",
+            "db_path": "${env.SQLITE_STORE_DIR:=" + __distro_dir__ + "}/" + db_name,
+        }
 
-    @property
-    def pip_packages(self) -> list[str]:
-        return super().pip_packages + ["aiosqlite"]
+    @classmethod
+    def pip_packages(cls) -> list[str]:
+        return super().pip_packages() + ["aiosqlite"]
 
 
 class PostgresSqlStoreConfig(SqlAlchemySqlStoreConfig):
     type: Literal["postgres"] = SqlStoreType.postgres.value
     host: str = "localhost"
-    port: str = "5432"
+    port: int = 5432
     db: str = "llamastack"
     user: str
     password: str | None = None
@@ -70,20 +70,20 @@ class PostgresSqlStoreConfig(SqlAlchemySqlStoreConfig):
     def engine_str(self) -> str:
         return f"postgresql+asyncpg://{self.user}:{self.password}@{self.host}:{self.port}/{self.db}"
 
-    @property
-    def pip_packages(self) -> list[str]:
-        return super().pip_packages + ["asyncpg"]
+    @classmethod
+    def pip_packages(cls) -> list[str]:
+        return super().pip_packages() + ["asyncpg"]
 
     @classmethod
     def sample_run_config(cls, **kwargs):
-        return cls(
-            type="postgres",
-            host="${env.POSTGRES_HOST:=localhost}",
-            port="${env.POSTGRES_PORT:=5432}",
-            db="${env.POSTGRES_DB:=llamastack}",
-            user="${env.POSTGRES_USER:=llamastack}",
-            password="${env.POSTGRES_PASSWORD:=llamastack}",
-        )
+        return {
+            "type": "postgres",
+            "host": "${env.POSTGRES_HOST:=localhost}",
+            "port": "${env.POSTGRES_PORT:=5432}",
+            "db": "${env.POSTGRES_DB:=llamastack}",
+            "user": "${env.POSTGRES_USER:=llamastack}",
+            "password": "${env.POSTGRES_PASSWORD:=llamastack}",
+        }
 
 
 SqlStoreConfig = Annotated[
@@ -92,6 +92,20 @@ SqlStoreConfig = Annotated[
 ]
 
 
+def get_pip_packages(store_config: dict | SqlStoreConfig) -> list[str]:
+    """Get pip packages for SQL store config, handling both dict and object cases."""
+    if isinstance(store_config, dict):
+        store_type = store_config.get("type")
+        if store_type == "sqlite":
+            return SqliteSqlStoreConfig.pip_packages()
+        elif store_type == "postgres":
+            return PostgresSqlStoreConfig.pip_packages()
+        else:
+            raise ValueError(f"Unknown SQL store type: {store_type}")
+    else:
+        return store_config.pip_packages()
+
+
 def sqlstore_impl(config: SqlStoreConfig) -> SqlStore:
     if config.type in [SqlStoreType.sqlite.value, SqlStoreType.postgres.value]:
         from .sqlalchemy_sqlstore import SqlAlchemySqlStoreImpl