docs(CHANGELOG): add download route + download_urls entry

Author: PM-Labs

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+- Pathfinder fork: bearer-authed `GET /images/:storage_id.png` route on the OAuth sidecar for local downloads.
+- `download_urls[]` field in `generate_image` `structured_content` (requires `NANOBANANA_PUBLIC_URL` env).
+- `NANOBANANA_PUBLIC_URL` env var.
+
 ## [0.4.4] - 2026-03-27
 
 ### Fixed