docs(changelog): mention Dockerfile Bun install (#284)

The build script was updated to use Bun (`bun scripts/canvas-a2ui-copy.ts`)
but the Dockerfile was not updated to install Bun, causing Docker builds to fail
with "bun: not found".

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -19,6 +19,7 @@
 - Configure: add OpenAI Codex (ChatGPT OAuth) auth choice (align with onboarding).
 - Doctor: suggest adding the workspace memory system when missing (opt-out via `--no-workspace-suggestions`).
 - Build: fix duplicate protocol export, align Codex OAuth options, and add proper-lockfile typings.
+- Build: install Bun in the Dockerfile so `pnpm build` can run Bun scripts. Thanks @loukotal for PR #284.
 - Typing indicators: stop typing once the reply dispatcher drains to prevent stuck typing across Discord/Telegram/WhatsApp.
 - Typing indicators: fix a race that could keep the typing indicator stuck after quick replies. Thanks @thewilloftheshadow for PR #270.
 - Google: merge consecutive messages to satisfy strict role alternation for Google provider models. Thanks @Asleep123 for PR #266.

Dockerfile

@@ -1,5 +1,9 @@
 FROM node:22-bookworm
 
+# Install Bun (required for build scripts)
+RUN curl -fsSL https://bun.sh/install | bash
+ENV PATH="/root/.bun/bin:${PATH}"
+
 RUN corepack enable
 
 WORKDIR /app