docs: update release notes with OpenCode bootstrap change

RELEASE-NOTES.md

@@ -11,6 +11,7 @@
 ### OpenCode Fixes
 
 - **Skills path consistency** — the bootstrap text no longer advertises a misleading `configDir/skills/superpowers/` path that didn't match the runtime path. The agent should use the native `skill` tool, not navigate to files by path. Tests now use consistent paths derived from a single source of truth. (#847, #916)
+- **Bootstrap as user message** — moved bootstrap injection from `experimental.chat.system.transform` to `experimental.chat.messages.transform`, prepending to the first user message instead of adding a system message. Avoids token bloat from system messages repeated every turn (#750) and fixes compatibility with Qwen and other models that break on multiple system messages (#894).
 
 ## v5.0.6 (2026-03-24)