feat: add FastAPI admin dashboard with sync orchestration and test suite

Replace Flask admin with FastAPI app (api/app/) featuring:
- Dashboard with stat cards, sync control, and history
- Mappings CRUD for ARTICOLE_TERTI with CSV import/export
- Article autocomplete from NOM_ARTICOLE
- SKU pre-validation before import
- Sync orchestration: read JSONs -> validate -> import -> log to SQLite
- APScheduler for periodic sync from UI
- File logging to logs/sync_comenzi_YYYYMMDD_HHMMSS.log
- Oracle pool None guard (503 vs 500 on unavailable)

Test suite:
- test_app_basic.py: 30 tests (imports + routes) without Oracle
- test_integration.py: 9 integration tests with Oracle

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

api/app/routers/mappings.py

@@ -0,0 +1,84 @@
+from fastapi import APIRouter, Query, Request, UploadFile, File
+from fastapi.responses import StreamingResponse, HTMLResponse
+from fastapi.templating import Jinja2Templates
+from pydantic import BaseModel
+from pathlib import Path
+from typing import Optional
+import io
+
+from ..services import mapping_service, sqlite_service
+
+router = APIRouter(tags=["mappings"])
+templates = Jinja2Templates(directory=str(Path(__file__).parent.parent / "templates"))
+
+class MappingCreate(BaseModel):
+    sku: str
+    codmat: str
+    cantitate_roa: float = 1
+    procent_pret: float = 100
+
+class MappingUpdate(BaseModel):
+    cantitate_roa: Optional[float] = None
+    procent_pret: Optional[float] = None
+    activ: Optional[int] = None
+
+# HTML page
+@router.get("/mappings", response_class=HTMLResponse)
+async def mappings_page(request: Request):
+    return templates.TemplateResponse("mappings.html", {"request": request})
+
+# API endpoints
+@router.get("/api/mappings")
+def list_mappings(search: str = "", page: int = 1, per_page: int = 50):
+    return mapping_service.get_mappings(search=search, page=page, per_page=per_page)
+
+@router.post("/api/mappings")
+async def create_mapping(data: MappingCreate):
+    try:
+        result = mapping_service.create_mapping(data.sku, data.codmat, data.cantitate_roa, data.procent_pret)
+        # Mark SKU as resolved in missing_skus tracking
+        await sqlite_service.resolve_missing_sku(data.sku)
+        return {"success": True, **result}
+    except Exception as e:
+        return {"success": False, "error": str(e)}
+
+@router.put("/api/mappings/{sku}/{codmat}")
+def update_mapping(sku: str, codmat: str, data: MappingUpdate):
+    try:
+        updated = mapping_service.update_mapping(sku, codmat, data.cantitate_roa, data.procent_pret, data.activ)
+        return {"success": updated}
+    except Exception as e:
+        return {"success": False, "error": str(e)}
+
+@router.delete("/api/mappings/{sku}/{codmat}")
+def delete_mapping(sku: str, codmat: str):
+    try:
+        deleted = mapping_service.delete_mapping(sku, codmat)
+        return {"success": deleted}
+    except Exception as e:
+        return {"success": False, "error": str(e)}
+
+@router.post("/api/mappings/import-csv")
+async def import_csv(file: UploadFile = File(...)):
+    content = await file.read()
+    text = content.decode("utf-8-sig")
+    result = mapping_service.import_csv(text)
+    return result
+
+@router.get("/api/mappings/export-csv")
+def export_csv():
+    csv_content = mapping_service.export_csv()
+    return StreamingResponse(
+        io.BytesIO(csv_content.encode("utf-8-sig")),
+        media_type="text/csv",
+        headers={"Content-Disposition": "attachment; filename=mappings.csv"}
+    )
+
+@router.get("/api/mappings/csv-template")
+def csv_template():
+    content = mapping_service.get_csv_template()
+    return StreamingResponse(
+        io.BytesIO(content.encode("utf-8-sig")),
+        media_type="text/csv",
+        headers={"Content-Disposition": "attachment; filename=mappings_template.csv"}
+    )