Update README with links and section formatting

Author: PAXECT-Interface

README.md

@@ -23,6 +23,8 @@ Connect all operating systems and programming languages through one reproducible
 🔗 Explore the ecosystem:  
 👉 [**PAXECT Universal Bridge →**](https://github.com/PAXECT-Interface/paxect-universal-bridge)
 
+> Looking for the full bundle (Core + plugins + demos)? See **[PAXECT Core Complete →](../paxect-core-complete)**
+
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 # PAXECT Core — The Multi-OS Bridge Engine