fix: treat reasoning_effort="none" as thinking disabled and route gemma to Gemini provider

- Do not send reasoning_effort="none" to APIs (prevents 400 on gemma/Gemini)
- Treat "none" as thinking disabled in thinking_style, Kimi, and reasoning_content backfill paths
- Fix Anthropic extended thinking not respecting "none"
- Fix Azure OpenAI temperature suppression and reasoning body for "none"
- Fix Codex reasoning body for "none"
- Add "gemma" keyword to Gemini ProviderSpec for correct auto routing

nanobot/providers/openai_compat_provider.py

@@ -570,7 +570,7 @@ class OpenAICompatProvider(LLMProvider):
             # DashScope accepts none/minimum/low/medium/high/xhigh; "minimal" 400s.
             wire_effort = "minimum"
 
-        if wire_effort:
+        if wire_effort and semantic_effort != "none":
             kwargs["reasoning_effort"] = wire_effort
 
         # Provider-specific thinking parameters.
@@ -579,7 +579,7 @@ class OpenAICompatProvider(LLMProvider):
         # The mapping is driven by ProviderSpec.thinking_style so that adding
         # a new provider never requires touching this function.
         if spec and spec.thinking_style and reasoning_effort is not None:
-            thinking_enabled = semantic_effort != "minimal"
+            thinking_enabled = semantic_effort not in ("none", "minimal")
             extra = _THINKING_STYLE_MAP.get(spec.thinking_style, lambda _: None)(thinking_enabled)
             if extra:
                 kwargs.setdefault("extra_body", {}).update(extra)
@@ -589,7 +589,7 @@ class OpenAICompatProvider(LLMProvider):
         # so that OpenRouter-style names like "moonshotai/kimi-k2.5" are handled
         # identically to bare names like "kimi-k2.5".
         if reasoning_effort is not None and _is_kimi_thinking_model(model_name):
-            thinking_enabled = semantic_effort != "minimal"
+            thinking_enabled = semantic_effort not in ("none", "minimal")
             kwargs.setdefault("extra_body", {}).update(
                 {"thinking": {"type": "enabled" if thinking_enabled else "disabled"}}
             )
@@ -609,9 +609,9 @@ class OpenAICompatProvider(LLMProvider):
         # thinking happened on that turn").
         thinking_active = (
             (spec and spec.thinking_style and reasoning_effort is not None
-             and semantic_effort != "minimal")
+             and semantic_effort not in ("none", "minimal"))
             or (reasoning_effort is not None and _is_kimi_thinking_model(model_name)
-                and semantic_effort != "minimal")
+                and semantic_effort not in ("none", "minimal"))
         )
         if thinking_active:
             for msg in kwargs["messages"]: