feat: add ITreasuryModule interface for treasury modules

contract/src/ITreasuryModule.cairo

@@ -0,0 +1,40 @@
+
+// ITreasuryModule.cairo
+// Cairo 1 interface for Treasury Modules
+
+#[starknet::interface]
+trait ITreasuryModule {
+    /// Executes a transfer of funds from the treasury.
+    ///
+    /// Args:
+    ///     * `token_address` - The address of the token to transfer.
+    ///     * `recipient` - The address of the recipient.
+    ///     * `amount` - The amount to transfer.
+    fn execute_transfer(
+        ref self: ContractState,
+        token_address: ContractAddress,
+        recipient: ContractAddress,
+        amount: u256
+    );
+
+    /// Sets the governance module that can control this treasury.
+    ///
+    /// Args:
+    ///     * `new_governance_module` - The address of the new governance module.
+    fn set_governance_module(
+        ref self: ContractState,
+        new_governance_module: ContractAddress
+    );
+
+    /// Returns the balance of a given token in the treasury.
+    ///
+    /// Args:
+    ///     * `token_address` - The address of the token to check.
+    ///
+    /// Returns:
+    ///     * `u256` - The balance of the token.
+    fn get_balance(
+        self: @ContractState,
+        token_address: ContractAddress
+    ) -> u256;
+}