docs: add CHANGELOG.md

Author: ranaroussi

CHANGELOG.md

@@ -0,0 +1,14 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+## [Unreleased]
+
+### Added
+- `mode` parameter in `FormationConfig` for draft/live URL routing
+  - `mode="live"` (default): Uses `/api/{id}/v1` prefix
+  - `mode="draft"`: Uses `/draft/{id}/v1` prefix for local development with `muxi up`
+- SDK version update notifications (via `X-Muxi-SDK-Latest` response header)
+  - Notifies when newer SDK version available (max once per 12 hours)
+  - Disable with `MUXI_SDK_VERSION_NOTIFICATION=0`
+- Console telemetry support via internal `_app` parameter