Enhance pty utils:
* Support closing stdin
* Separate stderr and stdout streams to allow consumers differentiate them
* Provide compatibility helper to merge both streams back into combined one
* Support specifying terminal size for pty, including on-demand resizes while process is already running
* Support terminating the process while still consuming its outputs
- override startup tooltips with model availability NUX and persist
per-model show counts in config
- stop showing each model after four exposures and fall back to normal
tooltips
