docs(readme): add a friendly star CTA to the header (#46)

One line after the value prop inviting a GitHub star, with the honest
reason (helps others discover it + surfaces us in MCP directories).
No live star-count badge yet by design. Part of the star-campaign plan.

Co-authored-by: MNEMOVERSE Developer <dev@mnemoverse.local>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: 3 people

README.md

@@ -11,6 +11,8 @@ Hosted memory for AI agents that learns and forgets. Feedback reranks the facts
 
 Memory that persists across sessions, projects, and tools — and improves with use. Hosted, so there's no infrastructure to run, and not locked to a single cloud.
 
+> ⭐ If Mnemoverse saves you from re-explaining context to your agents, [star the repo](https://github.com/mnemoverse/mcp-memory-server). It helps other builders find it.
+
 ## Quick Start
 
 ### 1. Get a free API key