feat: add Requesty as a model provider

Add Requesty (https://requesty.ai), an OpenAI-compatible LLM router, as a
model provider by mirroring the existing OpenRouter integration.

Backend:
- app/services/requesty_model_normalizer.py: normalizes Requesty's /v1/models
  catalogue, mapping its flat capability booleans (supports_tool_calling/
  supports_vision/supports_image_generation) and context_window field onto the
  shared normalized shape (Requesty differs from OpenRouter's architecture +
  supported_parameters + context_length layout)
- provider_registry.py: Requesty ProviderSpec (OpenAI-compatible, base URL
  https://router.requesty.ai/v1, REQUESTY_API_KEY bearer auth)
- model_connection_service.py: key verification + live model discovery
- quality_score.py: Requesty score entry
- unit tests mirroring the OpenRouter normalizer coverage

Frontend:
- Requesty provider icon + registration, metadata entry, and base-url hint

Signed-off-by: Thibault Jaigu <thibault.jaigu@gmail.com>

surfsense_backend/tests/unit/services/test_requesty_model_normalizer.py

@@ -0,0 +1,107 @@
+"""Unit tests for Requesty model normalization.
+
+Mirrors the OpenRouter normalizer coverage but exercises Requesty's flat
+boolean capability fields (``supports_tool_calling`` / ``supports_vision``)
+and ``context_window`` sizing.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from app.services.requesty_model_normalizer import (
+    is_requesty_chat_model,
+    is_requesty_image_model,
+    normalize_requesty_models,
+    supports_image_input,
+    supports_tool_calling,
+)
+
+pytestmark = pytest.mark.unit
+
+
+def _requesty_model(
+    *,
+    model_id: str,
+    context_window: int = 128_000,
+    tools: bool = True,
+    vision: bool = False,
+    image_generation: bool = False,
+    name: str | None = None,
+) -> dict:
+    """Return a synthetic Requesty ``/v1/models`` entry.
+
+    Only the fields the normalizer inspects are populated; the live payload
+    carries many more (pricing, ``supports_caching``, ``description``, ...).
+    """
+    return {
+        "id": model_id,
+        "name": name or model_id,
+        "api": "chat",
+        "object": "model",
+        "context_window": context_window,
+        "supports_tool_calling": tools,
+        "supports_vision": vision,
+        "supports_image_generation": image_generation,
+    }
+
+
+def test_chat_model_requires_slash_tools_and_context():
+    assert is_requesty_chat_model(_requesty_model(model_id="openai/gpt-4o-mini"))
+    assert not is_requesty_chat_model(
+        _requesty_model(model_id="openai/gpt-4o-mini", tools=False)
+    )
+    assert not is_requesty_chat_model(
+        _requesty_model(model_id="openai/gpt-4o-mini", context_window=8_000)
+    )
+    assert not is_requesty_chat_model(_requesty_model(model_id="bare-model"))
+
+
+def test_excluded_provider_slug_is_filtered():
+    assert not is_requesty_chat_model(
+        _requesty_model(model_id="amazon/nova-pro-v1")
+    )
+
+
+def test_image_generation_models_excluded_from_chat_and_flagged():
+    image_model = _requesty_model(
+        model_id="google/gemini-2.5-flash-image", image_generation=True
+    )
+    assert not is_requesty_chat_model(image_model)
+    assert is_requesty_image_model(image_model)
+
+
+def test_capability_helpers_read_flat_booleans():
+    model = _requesty_model(
+        model_id="anthropic/claude-sonnet-4-5", vision=True, tools=True
+    )
+    assert supports_image_input(model) is True
+    assert supports_tool_calling(model) is True
+
+
+def test_normalize_maps_context_window_and_capabilities():
+    normalized = normalize_requesty_models(
+        [
+            _requesty_model(
+                model_id="openai/gpt-4o-mini",
+                context_window=128_000,
+                vision=True,
+                name="GPT-4o mini",
+            ),
+            _requesty_model(model_id="openai/gpt-4o-mini", tools=False),
+            _requesty_model(
+                model_id="black-forest-labs/flux", image_generation=True
+            ),
+        ]
+    )
+
+    assert len(normalized) == 1
+    entry = normalized[0]
+    assert entry["model_id"] == "openai/gpt-4o-mini"
+    assert entry["display_name"] == "GPT-4o mini"
+    assert entry["supports_chat"] is True
+    assert entry["max_input_tokens"] == 128_000
+    assert entry["supports_image_input"] is True
+    assert entry["supports_tools"] is True
+    assert entry["supports_image_generation"] is False
+    assert entry["metadata"]["id"] == "openai/gpt-4o-mini"