fix(llm): disable Gemini thinking to prevent MAX_TOKENS on structured output

Gemini 2.5 Flash (gemini-flash-latest) enables thinking by default.
Thinking tokens count toward max_output_tokens, leaving ~150 tokens for
actual JSON output and causing MAX_TOKENS truncation. Disable thinking
centrally in call_gemini via ThinkingConfig(thinking_budget=0).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/innercontext/llm.py

@@ -46,6 +46,13 @@ def call_gemini(
         with suppress(Exception):
             user_input = str(contents)
 
+    # Disable thinking by default — Gemini 2.5 Flash thinking tokens count toward
+    # max_output_tokens, leaving too little room for actual JSON output.
+    if config.thinking_config is None:
+        config = config.model_copy(
+            update={"thinking_config": genai_types.ThinkingConfig(thinking_budget=0)}
+        )
+
     start = time.monotonic()
     success, error_detail, response, finish_reason = True, None, None, None
     try: