refacto: add build and cleanup file structure

src/config.sql

@@ -0,0 +1,59 @@
+-- =============================================================================
+-- CONFIGURATION
+-- =============================================================================
+-- Centralized configuration for morbac_pg extension
+-- Edit these values to customize behavior
+
+CREATE TABLE morbac.config (
+    key TEXT PRIMARY KEY,
+    value TEXT NOT NULL,
+    description TEXT,
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+COMMENT ON TABLE morbac.config IS 'Extension configuration - edit values to customize behavior';
+
+-- Insert default configuration values
+INSERT INTO morbac.config (key, value, description) VALUES
+    ('cache_ttl_seconds', '300', 'Authorization cache time-to-live in seconds (default: 5 minutes)'),
+    ('hierarchy_max_depth', '10', 'Maximum depth for hierarchy traversal to prevent infinite loops'),
+    ('enable_audit_by_default', 'false', 'Whether to enable audit logging by default on installation');
+
+-- Helper function to get configuration values
+CREATE OR REPLACE FUNCTION morbac.get_config(p_key TEXT)
+RETURNS TEXT
+LANGUAGE plpgsql
+STABLE
+AS $$
+DECLARE
+    v_value TEXT;
+BEGIN
+    SELECT value INTO v_value FROM morbac.config WHERE key = p_key;
+    RETURN v_value;
+EXCEPTION
+    WHEN OTHERS THEN
+        RETURN NULL;
+END;
+$$;
+
+COMMENT ON FUNCTION morbac.get_config(TEXT) IS
+'Get configuration value by key';
+
+-- Helper function to set configuration values
+CREATE OR REPLACE FUNCTION morbac.set_config(p_key TEXT, p_value TEXT)
+RETURNS VOID
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    UPDATE morbac.config
+    SET value = p_value, updated_at = CURRENT_TIMESTAMP
+    WHERE key = p_key;
+
+    IF NOT FOUND THEN
+        RAISE EXCEPTION 'Configuration key % does not exist', p_key;
+    END IF;
+END;
+$$;
+
+COMMENT ON FUNCTION morbac.set_config(TEXT, TEXT) IS
+'Set configuration value by key';