initial: multi-memory provider reference

Saved from the fork's patches/multi-memory branch. Contains the refactored
agent/memory_manager.py that supports N memory providers simultaneously.

Not active — stored for future reference.
- agent_memory_manager_patched.py (the refactored version)
- agent_memory_manager_original.py (upstream version for comparison)
- plugin.yaml + README

plugin.yaml

@@ -0,0 +1,8 @@
+name: multimemory
+version: 1.0.0
+description: >
+  Multi-memory provider plugin for Hermes. Allows running multiple memory
+  backends (Honcho, Mem0, SuperMemory, etc.) simultaneously. This is a
+  reference/save of the patched agent/memory_manager.py from the fork.
+  NOT currently active — kept for future use.
+author: "@gortium"