Feature: Building the missing pieces (API, Webhooks, Dark Mode, & Admin UI)

Hey,
I gave the agentic-inbox a spin tonight and realized it was missing the agentic part

What I've already built and tested:

The API: built the backend logic for programmatic sending (includes internal API key management and documentation for bypassing Zero Trust via Service Tokens.).

Webhook System: receiving emails.

Admin UI & Dark Mode: Overhauled the admin section to handle API/Webhook management and added a native dark mode toggle.

I saw some of these were requested or hinted at in other issues, so I just knocked them all out in one go.
I've got the PR ready to roll whenever you guys are down to take a look. Let me know!

[https://github.com/simonserghini/agentic-inbox](https://github.com/simonserghini/agentic-inbox)

[serghini.me](https://serghini.me)