Better Callout Shape

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Is your feature request related to a problem? Please describe.
I love draw.io - I use it every day (desktop version as well as embedded in Confluence). It's by far the best diagraming tool I've found. It's great for adhoc interactive collaboration sessions as well as creating lasting documentation. There's exactly one thing it's missing that causes me to use other tools - weak callout shape. I'm regularly creating diagrams to illustrate ideas to other people and teams and I need a way to annotate commentary on segments of the illustration. However, the callout shape and it's pointer just isn't flexible enough. I can't move the pointer much at all making it impossible to point it at the relevant segment. I think you can see others asking about that here: https://github.com/jgraph/drawio/discussions/4139

Describe the solution you'd like
I want a callout shape that allows me to freely move the pointer to any point on the diagram (up, down, left, right). If you look at the callout shape in Powerpoint - this is what draw.io needs. I frequently use powerpoint for diagraming instead of draw.io specifically for this micro feature.

Describe alternatives you've considered
You have to really clutter up your diagram to use the callout as it has to be almost overlaying the content you want to annotate. Or not use callouts at all and instead have text blocks or something else crude like that. My primary alternative today sad: I capture an image of the diagram I've draw in draw.io, paste it into powerpoint and I use call outs in powerpoint to overlay what I want on the image. This is really tedious and creates unmaintainable artifacts, but it's what I've had to resort to doing.

Start by reviewing the existing callout shape behavior in draw.io and the related discussion at github.com/jgraph/drawio/discussions/4139. Compare it with PowerPoint callouts and define how freely moving the pointer should work in all directions; the feature is done when callouts can target arbitrary diagram points without requiring overlays or separate text blocks.