Add Overloop CLI and Signals CLI to Applications

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Adds two open-source CLI tools to the Applications section in alphabetical order:

• overloop-cli — AI-powered outbound engine. Source contacts, run multi-channel campaigns (email + LinkedIn), and manage conversations. JSON output. Install: npm install -g overloop-cli
• signals-cli — B2B intent signal monitoring. Track LinkedIn engagement, keyword posters, job changers, and funding events. JSON output. Install: npm install -g signals-sortlist-cli

Both are Node.js CLI tools with JSON output, actively maintained and open source.