feat: forward reasoning_effort to the backend so jinja models honor it (#10184)

* feat: forward reasoning_effort to the backend so jinja models honor it

reasoning_effort was only mapped to the binary enable_thinking toggle and
otherwise reached Go-side templates — it was never sent to the backend. So
jinja-templated models whose chat template keys on reasoning_effort (gpt-oss
Harmony, LFM2.5) could not be driven by it: LFM2.5 ignores enable_thinking and
kept emitting <think>.

Forward the effective reasoning_effort to the backend as a chat_template_kwarg
(mirroring enable_thinking) in grpc-server.cpp, and put it in PredictOptions
metadata (gRPCPredictOpts). Add a config-level default: ModelConfig.reasoning_effort
and Pipeline.reasoning_effort, resolved by ModelConfig.ApplyReasoningEffort
(request value overrides config default, none->disable / level->enable, an
operator's reasoning.disable wins). request.go now uses that helper.

Assisted-by: Claude:claude-opus-4-8 go test, golangci-lint
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* feat(realtime): set the pipeline LLM's reasoning_effort

Apply Pipeline.ReasoningEffort to the pipeline's LLM config when the realtime
model is built (per-session copy, overrides the LLM's own reasoning_effort),
and surface the resolved effort on the template input so Go-templated models
get it too. jinja models receive it via the backend metadata. This lets a
realtime pipeline disable thinking on models that only honor reasoning_effort
(e.g. LFM2.5), which enable_thinking can't.

Assisted-by: Claude:claude-opus-4-8 go test, golangci-lint
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

---------

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

docs/content/advanced/model-configuration.md

@@ -418,6 +418,26 @@ This is the load-time reasoning configuration. The orthogonal per-request `enabl
 - `reasoning_effort: "minimal" | "low" | "medium" | "high"` enables thinking, unless the model config explicitly set `reasoning.disable: true` (an operator's explicit disable wins and is never re-enabled by a request).
 {{% /notice %}}
 
+#### `reasoning_effort` as a chat-template kwarg
+
+`reasoning_effort` is also forwarded to the backend as a `chat_template_kwarg`, so models whose **jinja chat template** keys on it — e.g. gpt-oss (Harmony) or LFM2.5 — honor the **level**, not just the on/off `enable_thinking` flag. This matters for models that ignore `enable_thinking` entirely (LFM2.5 keeps emitting `<think>` for `enable_thinking=false`, but respects `reasoning_effort`).
+
+Set a per-model default in the config so every request inherits it (a per-request `reasoning_effort` still overrides):
+
+```yaml
+name: my-model
+reasoning_effort: none   # none | minimal | low | medium | high
+```
+
+For [realtime pipelines]({{%relref "docs/features/openai-realtime" %}}), set it on the pipeline so it applies to the pipeline's LLM without editing that model's own config:
+
+```yaml
+name: gpt-realtime
+pipeline:
+  llm: lfm2.5
+  reasoning_effort: none   # overrides the LLM model's own reasoning_effort
+```
+
 ### Multimodal Backend Options
 
 | Option | Type | Default | Description |