v3.9.6: update CHANGELOG.md

CHANGELOG.md

@@ -1,5 +1,39 @@
 # Changelog
 
+## v3.9.6 (2026-05-25)
+
+**Fix Gemini Follow-Up Turns — tool_calls=0 Issue**
+
+### Root Cause
+The Antigravity adapter was dropping the latest user instruction during content
+sanitization and capping. Raw Codex items grew (13, 15, 17, 19) but Gemini contents
+stayed frozen at 12. Gemini received stale context and returned text-only responses
+instead of tool calls.
+
+### Fixes
+- **Enforce latest user instruction as final turn**: runs after all compaction/capping.
+  If the user's message was stripped, it's appended as the last content before POST.
+- **Edit-intent detection + tool-use nudge**: when follow-up requests contain edit
+  keywords (change, fix, redesign, etc.) and have prior tool history, injects a
+  forced tool-use instruction before POST.
+- **Debug logging**: before every Antigravity POST, logs contents count, latest user
+  text, and final content preview.
+- **Fixed needle validation**: handles newlines in user messages correctly.
+
+### Also includes (v3.9.3–v3.9.5)
+- Gemini 3 thought signature preservation (capture + reattach)
+- `thought_signature` field on all functionCall parts (snake_case, as API requires)
+- Fallback to `skip_thought_signature_validator` when no real signature
+- Tool output compaction: old 3000 chars, recent 6 at 20000 chars
+- Follow-through guardrail system instruction
+- Finish-reason diagnostics logging
+- Stream hang fix for function-call-only responses
+- Multi-account rotation for all providers (freebuff, Google, API keys)
+- `/v1/accounts` status endpoint
+
+---
+
+
 ## v3.9.0 (2026-05-24)
 
 **Multi-Account Rotation — Never Hit a Dead End Again**