chore(backend): remove recost telemetry middleware

The recost API key is revoked, so the middleware was logging an HTTP
401 on every request and adding latency for no benefit. Drop the import,
the env-var branch, and the requirements entry. Re-add cleanly later if
we get a working recost project + key.

Author: Darkest-Teddy

backend/main.py

@@ -1,4 +1,3 @@
-import os
 from pathlib import Path
 
 from dotenv import load_dotenv
@@ -11,25 +10,10 @@
 from routes.admin import router as admin_router
 from routes.newsletter import router as newsletter_router
 
-try:
-    from recost.frameworks.fastapi import RecostMiddleware
-except ImportError:
-    RecostMiddleware = None  # optional; tests/CI without recost package
-
 load_dotenv(Path(__file__).with_name(".env"))
 
-RECOST_PROJECT_ID = "eaf22d10-840d-494f-8513-2dcef769ace1"
-recost_api_key = os.getenv("RECOST_API_KEY")
-
 app = FastAPI(title="Sapling API", version="1.0.0")
 
-if recost_api_key and RecostMiddleware is not None:
-    app.add_middleware(
-        RecostMiddleware,
-        api_key=recost_api_key,
-        project_id=RECOST_PROJECT_ID,
-    )
-
 app.add_middleware(
     CORSMiddleware,
     allow_origins=[FRONTEND_URL, "http://localhost:3000"],

backend/requirements.txt

@@ -14,7 +14,6 @@ httpx
 cryptography>=42,<46
 mammoth
 python-pptx
-recost
 
 # OCR pipeline (Docling = default, GOT-OCR 2.0 = optional GPU fallback)
 docling>=2.15,<3