Over what distance would space combat between spacecraft probably occur given physical realities?

Many science fiction books invoke a naval combat paradigm when describing space combat: sensors and battleships with batteries, carriers with fighter-bombers, etc., usually over a distance of lightseconds.

Sometimes, they might even use something akin to submarines: "stealth" craft which may try to intercept communications, or conduct submarine like attacks.

However, would it be possible for space craft to really be "stealthy" or invisible to any degree in space, given that they must release some heat, but space is in general, utterly cold?

Would there be regions (apart from commonly invoked nebulae) which may mess with sensors?

What would stop spaceships from engaging in combat over the distance of lightyears, rather than lightseconds, if they are readily detectable from distances on the scale of lightyears?