fix: trim DeepInfra reasoning salvage to the invariant and document it

Follow-up to the cherry-picked #111876 (@KoNit-K), which shares the design
of the earlier #111875 by the issue author (@ats3v): emit DeepInfra's
top-level ``reasoning_effort`` from the provider profile, ungated on
``supports_reasoning``, ``none`` as the only off switch, ``xhigh`` native,
``ultra`` clamped to ``max`` via the shared vocabulary, unset/unknown omitted.

- drop the constructor/blank-line reformat churn (byte-identical to main)
- replace the 14-case test file with two invariant tests: the profile's
  config -> top-level field table, and the transport main-turn path with
  ``supports_reasoning=False`` (the gate the core allowlist actually passes)
- docs: DeepInfra subsection in integrations/providers.md describing the
  two-directional reasoning control

Offline kwargs probe: before every reasoning_config -> ({}, {}) and the
main turn carried no reasoning field; after ``high`` -> ``reasoning_effort:
high``, ``{'enabled': False}`` -> ``none``, ``ultra`` -> ``max``, unset and
unknown levels omitted, aux calls stop emitting the generic
``extra_body.reasoning`` for this provider.

Co-authored-by: Georgi Atsev <georgi@deepinfra.com>

plugins/model-providers/deepinfra/__init__.py

@@ -3,11 +3,7 @@ their own plugin subsystems)."""
 
 from typing import Any
 
-from agent.reasoning_effort import (
-    OPENAI_COMPAT_WIRE_EFFORTS,
-    clamp_effort,
-    requested_effort,
-)
+from agent.reasoning_effort import OPENAI_COMPAT_WIRE_EFFORTS, clamp_effort, requested_effort
 from providers import register_provider
 from providers.base import ProviderProfile
 
@@ -19,25 +15,19 @@ class _DeepInfraProfile(ProviderProfile):
     def build_api_kwargs_extras(
         self, *, reasoning_config: dict | None = None, **context: Any
     ) -> tuple[dict[str, Any], dict[str, Any]]:
-        """Map Hermes reasoning controls to DeepInfra's top-level wire field.
+        """Map Hermes reasoning controls to DeepInfra's top-level ``reasoning_effort``.
 
-        DeepInfra applies a per-model default when the field is absent, while
-        ``none`` is its explicit off switch. This route does not advertise a
-        reasoning capability to the shared transport, so it must not be gated
-        on ``supports_reasoning``.
+        DeepInfra applies a per-model default when the field is absent (DeepSeek-V4.x off,
+        GLM/Qwen-Thinking on), so ``none`` is the only working off switch and an unset effort
+        is omitted rather than guessed. The core ``_supports_reasoning_extra_body`` allowlist
+        does not know this host, so the transport always passes ``supports_reasoning=False``
+        here — gating on it would make the method a permanent no-op (#111872).
         """
-        if (
-            isinstance(reasoning_config, dict)
-            and reasoning_config.get("enabled") is False
-        ):
+        if isinstance(reasoning_config, dict) and reasoning_config.get("enabled") is False:
             return {}, {"reasoning_effort": "none"}
         effort = requested_effort(reasoning_config)
         clamped = clamp_effort(effort, OPENAI_COMPAT_WIRE_EFFORTS)
-        return (
-            ({}, {"reasoning_effort": clamped})
-            if clamped in OPENAI_COMPAT_WIRE_EFFORTS
-            else ({}, {})
-        )
+        return ({}, {"reasoning_effort": clamped}) if clamped in OPENAI_COMPAT_WIRE_EFFORTS else ({}, {})
 
     def default_vision_model(self):  # type: ignore[override]
         """First vision-capable *chat* model from the live catalog, or None. Key-gated so a box
@@ -49,7 +39,6 @@ class _DeepInfraProfile(ProviderProfile):
             return None
         try:
             from hermes_cli.models import _fetch_deepinfra_models_by_tag
-
             items = _fetch_deepinfra_models_by_tag("chat")
         except Exception:
             return None
@@ -62,13 +51,9 @@ class _DeepInfraProfile(ProviderProfile):
 
 
 deepinfra = _DeepInfraProfile(
-    name="deepinfra",
-    aliases=("deep-infra", "deepinfra-ai"),
-    display_name="DeepInfra",
-    description="DeepInfra — 100+ open models, pay-per-use",
-    signup_url="https://deepinfra.com/dash/api_keys",
-    env_vars=("DEEPINFRA_API_KEY", "DEEPINFRA_BASE_URL"),
-    base_url="https://api.deepinfra.com/v1/openai",
+    name="deepinfra", aliases=("deep-infra", "deepinfra-ai"), display_name="DeepInfra",
+    description="DeepInfra — 100+ open models, pay-per-use", signup_url="https://deepinfra.com/dash/api_keys",
+    env_vars=("DEEPINFRA_API_KEY", "DEEPINFRA_BASE_URL"), base_url="https://api.deepinfra.com/v1/openai",
     auth_type="api_key",
     default_max_tokens=None,  # DeepInfra applies its documented per-model limit
     # The only hardcoded DeepInfra model: aux resolution is synchronous, so it