feat(cli): add tab based slash command completion and prompt info completion

[kalvinnchau]

Per some discussion in https://github.com/block/goose/discussions/1401, some quality of life features for prompt commands in the cli

This does introduce a prompt cache that stores the information for the completion logic

• Add the ability to filter prompts by --extension to reduce the number of prompts
• Add Tab completion for /<Tab> all slash commands, and the ability to cycle through existing commands
• Add Tab completion for prompt names
• Add Tab completion for prompt arguments

Hard to see button presses, but <Tab> to cycle

https://github.com/user-attachments/assets/274ab952-2306-4816-a103-922df654d787