feat(memory): add optional alternative memory structure + pluggable LTM tools

[anilguleroglu]

Summary

Adds an optional alternative memory structure focused on single-invocation quality, without forcing long-term memory into the core loop.

What's included

• Optional working-memory tools (in-call):
  • wm_set_fact, wm_get_fact, wm_add_decision, wm_add_open_loop, wm_snapshot
• Optional LTM toolset via adapter:
  • ltm_write, ltm_search, and optional ltm_get / ltm_forget
• New memory options in agent config (memory):
  • enableWorkingMemoryTools
  • ltm.enabled + ltm.adapter
• SmartAgent tool injection wiring for the above
• Docs update in state-management guide
• Unit tests for memory tools

Why

Current memory flow is strong for single-call state/summarization, but this provides a structured working-memory layer and an optional LTM extension point.

Notes

• Backward compatible: memory tools are opt-in
• LTM remains separate from core behavior unless enabled