Add Overloop CLI and Signals CLI

[nifinet]

Adds two AI-powered B2B CLI tools to the ai category in data/apps.csv:

• Overloop CLI — AI-powered outbound engine. Source contacts, run multi-channel campaigns (email + LinkedIn), enroll prospects, and manage conversations. JSON output. https://github.com/sortlist/overloop-cli
• Signals CLI — B2B intent signal monitoring. Track LinkedIn engagement, job changers, funding events, and keyword posters. JSON output. https://github.com/sortlist/signals-cli

Both are open source and installable via npm.