Add resource monitor for constrained environments

[patmakesapps]

Problem

On a Raspberry Pi, resources are limited. Users need visibility into memory usage, model loading times, and warnings before running out of memory.

Proposed Solution

• Real-time memory/CPU display
• Model size recommendations based on available resources
• Warn before OOM errors
• Could show in CLI status bar

Acceptance Criteria

• Memory and CPU usage visible in the CLI
• Warnings when resources are low
• Suggests smaller model if memory is tight
• Does not add significant overhead