Add custom base images, private link sharing to Lovable clone guide

Add coming-soon items: custom base images via SSH snapshots,
private link sharing, and no-private-sharing limitation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: motatoes

docs/guides/build-a-lovable-clone.mdx

@@ -173,5 +173,6 @@ OpenComputer is building features that directly address these limitations:
 - **Secret sealing** — A secure mechanism for injecting secrets into sandboxes without exposing them in plain text. Sealed secrets will be encrypted at rest and only decrypted inside the sandbox at runtime, making it safe to pass API keys, database credentials, and other sensitive configuration.
 - **In-sandbox agent loop** — Instead of orchestrating the LLM from an external server (where every file write and command execution is a round-trip over the network), the agent loop will run _inside_ the sandbox itself. This dramatically reduces latency — the agent can read files, run commands, and iterate on errors locally without leaving the sandbox. It's also a simpler deployment model: you ship a single sandbox image with the agent baked in, rather than coordinating between an external server and a remote sandbox.
 - **Private link sharing** — The ability to share deploy preview URLs with specific people. You'll be able to grant access to individual team members or collaborators, so preview links aren't fully public but still don't require the recipient to have an OpenComputer account.
+- **Custom base images via SSH** — Instead of building templates solely from Dockerfiles, you'll be able to SSH into a running sandbox, install tools, configure files, and set up the environment exactly how you want it — then snapshot that sandbox as a base image. All future sandboxes created from that snapshot will start with your exact configuration pre-loaded, skipping lengthy setup steps like `npm install` or framework scaffolding.
 
 These additions will make it possible to build a production-grade app builder with full version history, secure secret handling, and robust deployment pipelines — all on top of OpenComputer sandboxes.