Add FastAPI endpoint and catalog loader

app/models.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from typing import Literal
+
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class MatchRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    messages: list[str] = Field(default_factory=list)
+
+
+class Candidate(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    sku: str
+    confidence: float = Field(ge=0.0, le=1.0)
+
+
+class MatchResult(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    message: str
+    status: Literal["matched", "ambiguous", "not_found"]
+    candidates: list[Candidate]
+
+
+class MatchResponse(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    results: list[MatchResult]