Add Scalekit (AgentKit & SaaSKit) to APIs & Backends

[saif-shines]

What

Adds both Scalekit products to the list, each in the section that fits best:

• Scalekit AgentKit → AI Coding Tools — Auth and tool-calling for AI agents with delegated OAuth, secure token vault, and 3000+ connectors.
• Scalekit SaaSKit → APIs & Backends — Full-stack authentication for B2B SaaS with Enterprise SSO, Directory Sync, and RBAC.

Why

Scalekit provides two complementary products targeting different audiences:

1. AgentKit enables AI agents to act on behalf of users across enterprise tools (Gmail, Slack, Jira, etc.) with proper OAuth consent, secure token management, and MCP support. It belongs in AI Coding Tools alongside the agents and assistants it powers.
2. SaaSKit is full-stack auth for B2B SaaS apps — hosted sign-in/up pages, session management, organizations, Enterprise SSO (SAML & OIDC), SCIM provisioning, and RBAC. It belongs in APIs & Backends alongside Firebase, Supabase, and Appwrite.

Changes

AI Coding Tools:

+ * [Scalekit AgentKit](https://scalekit.com/) - Auth and tool-calling for AI agents with delegated OAuth, secure token vault, and 3000+ connectors.

APIs & Backends:

+ * [Scalekit SaaSKit](https://scalekit.com/auth-for-saas) - Full-stack authentication for B2B SaaS with Enterprise SSO, Directory Sync, and RBAC.