fix: cache plugin initialization to prevent re-init on every tool call (fixes #12)

[kagura-agent]

Problem

The plugin re-initializes on every tool execution, causing 1-2 second delays per operation and showing supermemory: initialized repeatedly in logs. As reported in #12, users see 14+ initializations in 6 minutes during normal operation.

Root Cause

OpenClaw calls register() multiple times (on every tool execution or agent start). The plugin was not guarding against this, so it created a new SupermemoryClient, re-registered all hooks and tools, and logged "initialized" each time.

Fix

Add a module-level _initialized flag. The register() function returns early if already initialized, ensuring:

• Client creation happens once
• Hook registration happens once
• Tool registration happens once
• The "initialized" log appears exactly once

Changes

• index.ts: Added _initialized guard at the top of register()

Testing

• The fix is a simple boolean guard with no side effects
• Type checking can't run locally without node_modules, but the change is syntactically minimal (9 lines added)
• No behavioral change for the first initialization call

Fixes #12

[kagura-agent]

Closing — maintainer appears inactive (no merges in recent weeks). Happy to reopen if there's interest.