feat(routers): add executions, backups, and settings endpoints

backend/app/routers/settings.py

@@ -1,4 +1,43 @@
-from fastapi import APIRouter
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+from typing import List
+from app.database import get_db
+from app.models import Setting
+from app.schemas import Setting as SettingSchema, SettingUpdate
 
 router = APIRouter(prefix="/api/settings", tags=["settings"])
-# Will be implemented in later tasks
+
+@router.get("/", response_model=List[SettingSchema])
+async def list_settings(db: AsyncSession = Depends(get_db)):
+    result = await db.execute(select(Setting))
+    settings = result.scalars().all()
+    return settings
+
+@router.get("/{key}", response_model=SettingSchema)
+async def get_setting(key: str, db: AsyncSession = Depends(get_db)):
+    result = await db.execute(select(Setting).where(Setting.key == key))
+    setting = result.scalar_one_or_none()
+    if not setting:
+        raise HTTPException(status_code=404, detail="Setting not found")
+    return setting
+
+@router.put("/{key}", response_model=SettingSchema)
+async def update_setting(
+    key: str,
+    setting_update: SettingUpdate,
+    db: AsyncSession = Depends(get_db)
+):
+    result = await db.execute(select(Setting).where(Setting.key == key))
+    setting = result.scalar_one_or_none()
+    
+    if not setting:
+        # Create if not exists
+        setting = Setting(key=key, value=setting_update.value)
+        db.add(setting)
+    else:
+        setting.value = setting_update.value
+    
+    await db.commit()
+    await db.refresh(setting)
+    return setting