Add Gitea/Forgejo webhook support

[GodsBoy]

Support Gitea and Forgejo (Gitea fork) webhooks for self-hosted Git platforms.

Scope:

• Parse Gitea webhook payloads
• Map events to existing triage pipeline
• Add Gitea API client

Resources:

• Gitea Webhooks
• Similar structure to GitHub handler

Great for contributors familiar with Gitea or Forgejo.

[GodsBoy]

Thanks for suggesting Gitea/Forgejo webhook support! This is a great addition that would bring self-hosted Git platform support to the project. Since the payload structure is similar to GitHub, this should be achievable by implementing a webhook parser and API client following the existing handler patterns. A maintainer will review this and help coordinate with any interested contributors.