chore: align SDK with server #218 (max_completion_tokens, models)

Server PR interfaze#218 (OpenAI 1:1 spec-compat) is deploying:
- max_completion_tokens is now honored as an alias for max_tokens
  (max_tokens still wins), so drop the README guidance that said to
  avoid it.
- GET /v1/models is OpenAI-enveloped and GET /v1/models/{id} now exists;
  add mocked tests locking in models.list()/retrieve() including the
  spec-shaped model_not_found 404.

Author: Abhinavexist

README.md

@@ -119,8 +119,8 @@ URLs and base64 work; raw `bytes` do **not** (must be base64-encoded — this SD
 ## Good to know
 
 - Interfaze implements `chat.completions` and `models`; other OpenAI endpoints are not exposed.
-- `temperature` ≤ 1, `max_tokens` ≤ 32000, `top_p` ≤ 1 (above → 400). Use `max_tokens` (not
-  `max_completion_tokens`) to bound output.
+- `temperature` ≤ 1, `max_tokens` ≤ 32000, `top_p` ≤ 1 (above → 400). Both `max_tokens` and
+  `max_completion_tokens` bound output (`max_tokens` wins if both are set).
 - `n`, `seed`, `stop`, penalties, `logprobs`, `tool_choice`, `top_k` are ignored by Interfaze.
 - The underlying OpenAI client is available at `interfaze.openai`.
 

tests/test_models.py

@@ -0,0 +1,41 @@
+from __future__ import annotations
+
+import httpx
+import pytest
+import respx
+from openai import NotFoundError
+
+from interfaze import Interfaze
+
+MODELS_URL = "https://api.interfaze.ai/v1/models"
+MODEL = {"id": "interfaze-beta", "object": "model", "owned_by": "interfaze", "name": "Interfaze Beta"}
+MODELS_LIST = {"object": "list", "data": [MODEL]}
+NOT_FOUND = {
+    "error": {
+        "message": "The model 'nope' does not exist",
+        "type": "invalid_request_error",
+        "code": "model_not_found",
+    }
+}
+
+
+@respx.mock
+def test_models_list():
+    respx.get(MODELS_URL).mock(return_value=httpx.Response(200, json=MODELS_LIST))
+    page = Interfaze(api_key="t").models.list()
+    assert [m.id for m in page] == ["interfaze-beta"]
+    assert page.data[0].owned_by == "interfaze"
+
+
+@respx.mock
+def test_models_retrieve():
+    respx.get(f"{MODELS_URL}/interfaze-beta").mock(return_value=httpx.Response(200, json=MODEL))
+    m = Interfaze(api_key="t").models.retrieve("interfaze-beta")
+    assert m.id == "interfaze-beta" and m.owned_by == "interfaze"
+
+
+@respx.mock
+def test_models_retrieve_not_found():
+    respx.get(f"{MODELS_URL}/nope").mock(return_value=httpx.Response(404, json=NOT_FOUND))
+    with pytest.raises(NotFoundError):
+        Interfaze(api_key="t").models.retrieve("nope")