refactor: move model definitions into providers and extract resolve module

- Rename ImageProvider to BlackForestProvider, TextProvider to MistralProvider
- Add get_provided_models() abstract method to Provider base class
- Move model lists from models.py into each provider's get_provided_models()
- Add providers/registry.py to aggregate models from all providers
- Extract infer_required_capabilities and resolve_model from config.py to resolve.py
- Update tests to use new names and import paths

bulkgen/providers/image.py

@@ -1,89 +0,0 @@
-"""BlackForestLabs image generation provider."""
-
-from __future__ import annotations
-
-import base64
-from pathlib import Path
-from typing import override
-
-import httpx
-
-from bulkgen.config import TargetConfig
-from bulkgen.providers import Provider
-from bulkgen.providers.bfl import BFLClient
-from bulkgen.providers.models import ModelInfo
-
-
-def _encode_image_b64(path: Path) -> str:
-    """Read an image file and return its base64-encoded representation."""
-    return base64.b64encode(path.read_bytes()).decode("ascii")
-
-
-# Parameter names for reference images, keyed by model prefix.
-_INPUT_IMAGE_KEYS = ["input_image"] + [f"input_image_{i}" for i in range(2, 9)]
-_IMAGE_PROMPT_KEYS = ["image_prompt"]
-
-
-def _ref_image_keys(model: str) -> list[str]:
-    """Return the ordered API parameter names for reference images."""
-    if model.startswith("flux-2-"):
-        return _INPUT_IMAGE_KEYS  # up to 8
-    if model.startswith("flux-kontext-"):
-        return _INPUT_IMAGE_KEYS[:4]  # up to 4
-    return _IMAGE_PROMPT_KEYS  # flux 1.x: single image_prompt
-
-
-def _add_reference_images(
-    inputs: dict[str, object],
-    reference_images: list[str],
-    model: str,
-    project_dir: Path,
-) -> None:
-    """Encode reference images and add them under the correct API keys."""
-    keys = _ref_image_keys(model)
-    for key, ref_name in zip(keys, reference_images, strict=False):
-        inputs[key] = _encode_image_b64(project_dir / ref_name)
-
-
-class ImageProvider(Provider):
-    """Generates images via the BlackForestLabs API."""
-
-    _client: BFLClient
-
-    def __init__(self, api_key: str) -> None:
-        self._client = BFLClient(api_key=api_key)
-
-    @override
-    async def generate(
-        self,
-        target_name: str,
-        target_config: TargetConfig,
-        resolved_prompt: str,
-        resolved_model: ModelInfo,
-        project_dir: Path,
-    ) -> None:
-        output_path = project_dir / target_name
-
-        inputs: dict[str, object] = {"prompt": resolved_prompt}
-
-        if target_config.width is not None:
-            inputs["width"] = target_config.width
-        if target_config.height is not None:
-            inputs["height"] = target_config.height
-
-        if target_config.reference_images:
-            _add_reference_images(
-                inputs, target_config.reference_images, resolved_model.name, project_dir
-            )
-
-        for control_name in target_config.control_images:
-            ctrl_path = project_dir / control_name
-            inputs["control_image"] = _encode_image_b64(ctrl_path)
-
-        result = await self._client.generate(resolved_model.name, inputs)
-
-        async with httpx.AsyncClient() as http:
-            response = await http.get(result.sample_url)
-            _ = response.raise_for_status()
-
-        _ = output_path.write_bytes(response.content)