feat: Stable Diffusion 1.x MCPサーバを実装

仕様書・設計書に基づき、ローカルCUDA GPU上のStable Diffusion 1.x互換モデルをMCP経由で利用するサーバを新規実装。

実装内容:
- generate_image、generate_guided_image、inpaint_imageの3ツールをMCP SDK v2で公開
- TOMLからcheckpoint、VAE、複数LoRAと重み、ControlNet、生成設定を読み込み
- モデル種別ごとの固定ディレクトリ解決と起動時の設定・ファイル存在検証を追加
- Depth/MiDaS、OpenPose body/full、ControlNet Inpaintの前処理とパイプライン切替を実装
- FP16/CUDA、1枚固定生成、ControlNetオンデマンドロード、単一GPU直列実行を実装
- Base64 PNG/JPEG入力の形式・サイズ検証と任意のdata URI入力に対応
- seed、サイズ、モード、時刻、処理時間をPNG metadataへ記録
- 任意のローカルPNG保存、生成エラー分類、CUDA OOM後のキャッシュ回復を追加
- --configと--versionを備えたstdio CLIエントリポイントを追加

開発・運用:
- Python 3.11およびuvによる依存・lock管理を構成
- config.example.tomlとセットアップ・運用手順をREADMEへ追加
- Ruff、Pyright、pytestの設定を追加
- 設定、パス解決、schema、画像検証、サービスルーティング、排他制御、MCP画像返却をテスト

検証結果:
- pytest: 30 passed
- Ruff lint/format: passed
- Pyright: 0 errors, 0 warnings
- CLI versionおよびMCPクライアント経由のPNG返却を確認
- 実GPU smoke testはCUDA GPUとモデルファイルがないため対象外

1 files changed, 142 insertions, 0 deletions

diff --git a/src/mcp_sd15/schema.py b/src/mcp_sd15/schema.py
new file mode 100644
index 0000000..e22450d
--- /dev/null
+++ b/src/mcp_sd15/schema.py
@@ -0,0 +1,142 @@
+"""Validated request and response types independent of MCP and Diffusers."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from enum import StrEnum
+from typing import Any
+
+from .errors import InvalidRequestError
+
+
+class ImageSize(StrEnum):
+    SQUARE_512 = "square_512"
+    LANDSCAPE_512 = "landscape_512"
+    PORTRAIT_512 = "portrait_512"
+
+    @property
+    def dimensions(self) -> tuple[int, int]:
+        return {
+            ImageSize.SQUARE_512: (512, 512),
+            ImageSize.LANDSCAPE_512: (512, 384),
+            ImageSize.PORTRAIT_512: (384, 512),
+        }[self]
+
+
+class ControlMode(StrEnum):
+    DEPTH = "depth"
+    OPENPOSE = "openpose"
+    OPENPOSE_FULL = "openpose_full"
+
+
+def _prompt(value: Any, label: str, *, required: bool) -> str:
+    if value is None and not required:
+        return ""
+    if not isinstance(value, str):
+        raise InvalidRequestError(f"{label} must be a string")
+    value = value.strip()
+    if required and not value:
+        raise InvalidRequestError(f"{label} must not be empty")
+    if len(value) > 10_000:
+        raise InvalidRequestError(f"{label} is too long")
+    return value
+
+
+def _size(value: str | ImageSize | None, default: str) -> ImageSize:
+    try:
+        return ImageSize(value or default)
+    except ValueError as exc:
+        raise InvalidRequestError(f"unsupported size: {value}") from exc
+
+
+@dataclass(frozen=True)
+class TextToImageRequest:
+    positive_prompt: str
+    negative_prompt: str
+    size: ImageSize
+
+    @classmethod
+    def create(
+        cls,
+        positive_prompt: str,
+        negative_prompt: str | None = None,
+        size: str | ImageSize | None = None,
+        *,
+        default_size: str = ImageSize.SQUARE_512,
+    ) -> TextToImageRequest:
+        return cls(
+            _prompt(positive_prompt, "positive_prompt", required=True),
+            _prompt(negative_prompt, "negative_prompt", required=False),
+            _size(size, default_size),
+        )
+
+
+@dataclass(frozen=True)
+class GuidedImageRequest:
+    positive_prompt: str
+    negative_prompt: str
+    size: ImageSize
+    control_mode: ControlMode
+    input_image: str
+
+    @classmethod
+    def create(
+        cls,
+        positive_prompt: str,
+        control_mode: str | ControlMode,
+        input_image: str,
+        negative_prompt: str | None = None,
+        size: str | ImageSize | None = None,
+        *,
+        default_size: str = ImageSize.SQUARE_512,
+    ) -> GuidedImageRequest:
+        base = TextToImageRequest.create(
+            positive_prompt, negative_prompt, size, default_size=default_size
+        )
+        try:
+            mode = ControlMode(control_mode)
+        except ValueError as exc:
+            raise InvalidRequestError(f"unsupported control_mode: {control_mode}") from exc
+        if not isinstance(input_image, str) or not input_image.strip():
+            raise InvalidRequestError("input_image must be a non-empty Base64 string")
+        return cls(base.positive_prompt, base.negative_prompt, base.size, mode, input_image)
+
+
+@dataclass(frozen=True)
+class InpaintImageRequest:
+    positive_prompt: str
+    negative_prompt: str
+    size: ImageSize
+    input_image: str
+    mask_image: str
+
+    @classmethod
+    def create(
+        cls,
+        positive_prompt: str,
+        input_image: str,
+        mask_image: str,
+        negative_prompt: str | None = None,
+        size: str | ImageSize | None = None,
+        *,
+        default_size: str = ImageSize.SQUARE_512,
+    ) -> InpaintImageRequest:
+        base = TextToImageRequest.create(
+            positive_prompt, negative_prompt, size, default_size=default_size
+        )
+        for label, value in (("input_image", input_image), ("mask_image", mask_image)):
+            if not isinstance(value, str) or not value.strip():
+                raise InvalidRequestError(f"{label} must be a non-empty Base64 string")
+        return cls(
+            base.positive_prompt,
+            base.negative_prompt,
+            base.size,
+            input_image,
+            mask_image,
+        )
+
+
+@dataclass(frozen=True)
+class GenerationResult:
+    png_data: bytes
+    metadata: dict[str, str | int | float]