I would like to know how you handle ingame time compared to realtime? Lets say you play 2-3 times a month shadowrun, and your players want to code a programm, or create a spell formula aso. witch takes some time how do you handel the time flow? 1:1, or 1:2?

Variably. If a player says "I bind a Force 3 spirit", then the clock (for that character) moves forwards three hours. If a character says "I spend a month working on a program", then the clock for that character moves forward a month. If a player says "I work on a program until a fixer calls or something similar comes up", then GM decides how long that is.

Same as movies and TV: duration of elapsed time between scenes can be seconds or years - writer's choice.

My group ended last session with a cliffhanger freeze-frame mid-combat. 2 weeks have passed in realtime, but time is not passing in the game.

When we're not in combat time, GM enforces a houserule that if we spend an hour planning, our characters have spent at least an hour planning.

It depends.

When I run Missions games, I use their time tracking system. It works pretty well for keeping track of who did what when.

When I run a game like "Parliament of Thieves", I frequently put my watch on the table, and let everyone know that this adventure is happening in real time. If they have 3 in-game hours to finish the adventure, they have three hours on the watch, or they fail. I'll adjust the time for combat, since it takes quite a while; but since a lot of smaller things can be handwaved, I won't adjust the time a whole lot.