[wisdom-02] Add reference implementations section to INTEGRATION_GUIDE.md

[artugro]

Priority: P1 — Size: S

At the top of docs/INTEGRATION_GUIDE.md, link to:

• intuno-sdk — Python client
• samantha-foundation — full entity example with heartbeat / memory
• wisdom-agents catalog — static-config pattern

Readers currently have no pointer to worked examples.

Part of the 2026-04-22 cross-repo sync batch.