fix: Crof multi-turn tool calls + auto-trim long conversations

Root cause: Codex sends function_call items with id=None, causing
tool_call_id mismatch between tool calls and tool results. Proxy now
resolves IDs by call_id + positional fallback.

Auto-trim: conversations exceeding 30 items are trimmed automatically,
keeping system messages, original user query, and most recent items.
This prevents context overflow on providers with smaller context
windows (Crof mimo-v2.5-pro stops responding at ~40 items).

- Fix None tool IDs in oa_input_to_messages with positional matching
- Auto-trim input to 30 items max (keeps head + tail)
- Add request/response logging to ~/.cache/codex-proxy/requests.log
- Proxy stderr visible in launcher terminal for debugging
- v2.1.2

CHANGELOG.md

@@ -2,12 +2,15 @@
 
 ## v2.1.2 (2026-05-19)
 
-- **Fixed Crof.ai and other providers stopping after first tool call (root cause)**
-- Proxy now stores responses and resolves `previous_response_id` for multi-turn conversations
-- Codex Desktop uses `previous_response_id` to chain turns — proxy reconstructs full conversation context
-- Without this fix, the proxy sent only the new `function_call_output` to upstream without the original user message or assistant tool call, causing the upstream model to return incomplete responses
+- **Fixed Crof.ai and providers stopping after first tool call (root cause: None tool IDs)**
+- Codex sends `function_call` items with `id=None` — proxy now matches tool results to calls by call_id + positional fallback
 - Fixed orphan message output item when response is only tool calls (no text content)
-- Response store capped at 50 entries (LRU eviction)
+- **Auto-trims long conversations (>30 items)** to prevent context overflow on providers like Crof
+  - Keeps system/developer messages, original user query, and most recent items
+  - Drops oldest tool call/outputs from the middle when conversation grows too long
+  - Prevents `status=incomplete` errors on providers with smaller context windows
+- Added request/response logging to `~/.cache/codex-proxy/requests.log` for debugging
+- Proxy stderr no longer discarded by launcher (visible in terminal for debugging)
 
 ## v2.1.1 (2026-05-19)