Fixing a couple of small things

[joshka]

What do you want to change?

I found a couple of small bugs (with repros) - with AI while doing something eles

• a dead highlight.zig function that doesn't compile (Flattened.init)
• a memory leak in OSC color_operation cleanup

Why do you want to make this change?

First is just a small cleanup
second is a user controllable memory leak probably

I acknowledge that:

• I have read the Contributing Guide and understand the contribution process.
• I have read and agree to follow the AI Usage Policy.
• I wrote this vouch request myself, in my own voice, without AI generating it.