feat(cli): add interactive console navigation for multiple flow selections

[lemorage]

Closes #512.

Changes

Assuming we have defined two flows in the main.py.

Before this PR:

(cocoindex)$  uv run cocoindex show main.py
Usage: cocoindex show [OPTIONS] APP_FLOW_SPECIFIER
Try 'cocoindex show --help' for help.

Error: Multiple flows available, please specify which flow to target by appending :FlowName to the APP_TARGET.
Available: CodeEmbedding, TextEmbedding

After this PR (use up/down keys to navigate in the menu):

(cocoindex)$  uv run cocoindex show main.py
╭───────────────╮
│ Select a Flow │
╰───────────────╯
> CodeEmbedding
  TextEmbedding

[badmonster0]

Nice, thanks!!