refactor(ai_client): merge vendor_capabilities into ai_client; git rm src/vendor_capabilities.py

Per spec FR2 + Phase 2.1: VendorCapabilities + register + get_capabilities +
list_models_for_vendor + the ~40 vendor registrations move into ai_client.py
as a region block. Renamed internal _REGISTRY to _VENDOR_REGISTRY to avoid
collision with mcp_tool_specs._REGISTRY.

Importers (in src/) updated:
- src/ai_client.py: removed top-level import; removed 4 local imports of
  list_models_for_vendor/get_capabilities (symbol now in module namespace)
- src/app_controller.py: 2 sites updated to 'from src.ai_client import get_capabilities'
- src/gui_2.py: 1 site updated to 'from src.ai_client import VendorCapabilities, get_capabilities'

Tests updated:
- 8 test_*.py files: changed 'from src.vendor_capabilities import' to
  'from src.ai_client import'
- tests/test_vendor_capabilities.py: _clean_registry fixture updated to
  reference src.ai_client._VENDOR_REGISTRY (was src.vendor_capabilities._REGISTRY)

Verification: 157 tests pass across the affected files (vendor_capabilities,
ai_client_tool_loop variants, openai_compatible, command_palette,
diff_viewer, patch_modal, app_controller_result, app_controller_sigint,
handle_reset_session, ai_loop_regressions, grok/llama/minimax provider tests).

tests/test_ai_client_tool_loop.py

@@ -20,7 +20,7 @@ from src.result_types import Result
 from src.openai_compatible import NormalizedResponse, OpenAICompatibleRequest
 from src.openai_schemas import UsageStats
 from src.ai_client import run_with_tool_loop
-from src.vendor_capabilities import VendorCapabilities
+from src.ai_client import VendorCapabilities
 
 @pytest.fixture
 def caps() -> VendorCapabilities:

tests/test_ai_client_tool_loop_builder.py

@@ -11,7 +11,7 @@ from src.openai_compatible import NormalizedResponse, OpenAICompatibleRequest
 from src.openai_schemas import UsageStats
 from src.ai_client import run_with_tool_loop
 from src.result_types import Result
-from src.vendor_capabilities import VendorCapabilities
+from src.ai_client import VendorCapabilities
 
 def _make_normalized_response(text: str = "ok", tool_calls: list[dict[str, Any]] | None = None) -> NormalizedResponse:
  return NormalizedResponse(

tests/test_ai_client_tool_loop_send_func.py

@@ -9,7 +9,7 @@ from unittest.mock import MagicMock, patch
 from src.openai_compatible import NormalizedResponse
 from src.openai_schemas import UsageStats
 from src.ai_client import run_with_tool_loop
-from src.vendor_capabilities import VendorCapabilities
+from src.ai_client import VendorCapabilities
 
 def _make_normalized_response(text: str = "ok", tool_calls: list[dict[str, Any]] | None = None) -> NormalizedResponse:
  return NormalizedResponse(

tests/test_ai_loop_regressions_20260614.py

@@ -214,7 +214,7 @@ def test_fr3_minimax_thinking_in_returned_text() -> None:
  from src import openai_compatible as oc
  from src import provider_state
  from src.provider_state import ProviderHistory
- from src.vendor_capabilities import register, VendorCapabilities
+ from src.ai_client import register, VendorCapabilities
  register(VendorCapabilities(vendor="minimax", model="MiniMax-M2.7", reasoning=True))
  ai_client._model = "MiniMax-M2.7"
 

tests/test_grok_provider.py

@@ -23,7 +23,7 @@ def test_send_grok_uses_xai_endpoint(monkeypatch: pytest.MonkeyPatch) -> None:
   assert mock_client.chat.completions.create.called
 
 def test_grok_2_vision_supports_image() -> None:
- from src.vendor_capabilities import get_capabilities
+ from src.ai_client import get_capabilities
  caps = get_capabilities("grok", "grok-2-vision")
  assert caps.vision is True
 

tests/test_llama_provider.py

@@ -62,7 +62,7 @@ def test_llama_model_discovery_unions_ollama_and_openrouter() -> None:
  assert "llama-3.3-70b-specdec" in models
 
 def test_llama_3_2_vision_vision_capability() -> None:
- from src.vendor_capabilities import get_capabilities
+ from src.ai_client import get_capabilities
  caps = get_capabilities("llama", "llama-3.2-11b-vision-preview")
  assert caps.vision is True
 

tests/test_minimax_provider.py

@@ -42,7 +42,7 @@ def test_minimax_reasoning_extractor_used_when_caps_reasoning_true() -> None:
  def _fake_send(client, request, *, capabilities):
   captured_kwargs.append({"model": request.model})
   return MagicMock(text="ok", tool_calls=[], usage=UsageStats(input_tokens=0, output_tokens=0, cache_read_tokens=0, cache_creation_tokens=0), raw_response=None)
- from src.vendor_capabilities import register, VendorCapabilities
+ from src.ai_client import register, VendorCapabilities
  register(VendorCapabilities(vendor='minimax', model='MiniMax-M2.5', reasoning=True))
  with patch.object(oc, "send_openai_compatible", side_effect=_fake_send), \
       patch("src.ai_client._ensure_minimax_client", return_value=MagicMock()), \
@@ -54,7 +54,7 @@ def test_minimax_reasoning_extractor_omitted_when_caps_reasoning_false() -> None
  """caps.reasoning=False (M2/M2.1) should NOT pass the reasoning_extractor (avoid useless getattr)."""
  from src import openai_compatible as oc
  from src.openai_schemas import UsageStats
- from src.vendor_capabilities import register, VendorCapabilities
+ from src.ai_client import register, VendorCapabilities
  register(VendorCapabilities(vendor='minimax', model='MiniMax-M2', reasoning=False))
  captured_kwargs: list[dict] = []
  def _fake_send(client, request, *, capabilities):

tests/test_openai_compatible.py

@@ -6,7 +6,7 @@ from src.openai_compatible import (
  send_openai_compatible,
 )
 from src.openai_schemas import ChatMessage
-from src.vendor_capabilities import VendorCapabilities, register
+from src.ai_client import VendorCapabilities, register
 
 @pytest.fixture
 def caps() -> VendorCapabilities:

tests/test_vendor_capabilities.py

@@ -1,13 +1,13 @@
 import pytest
-from src.vendor_capabilities import VendorCapabilities, get_capabilities, register
+from src.ai_client import VendorCapabilities, get_capabilities, register
 
 @pytest.fixture(autouse=True)
 def _clean_registry():
- import src.vendor_capabilities
- snapshot = src.vendor_capabilities._REGISTRY.copy()
+ import src.ai_client as _ai
+ snapshot = _ai._VENDOR_REGISTRY.copy()
  yield
- src.vendor_capabilities._REGISTRY.clear()
- src.vendor_capabilities._REGISTRY.update(snapshot)
+ _ai._VENDOR_REGISTRY.clear()
+ _ai._VENDOR_REGISTRY.update(snapshot)
 
 def test_registry_lookup_known_model():
  caps = VendorCapabilities(
@@ -217,6 +217,6 @@ def test_v2_capability_badge_helper_skips_disabled_fields() -> None:
  a live context, but we can verify the helper is a no-op on
  the no-cap case.)"""
  from src.gui_2 import _render_v2_capability_badges
- from src.vendor_capabilities import VendorCapabilities
+ from src.ai_client import VendorCapabilities
  empty_caps = VendorCapabilities(vendor='test', model='empty')
  _render_v2_capability_badges(empty_caps)