chore: remove stale 2025-11-22 session summary

SESSION_CONTINUATION_SUMMARY.md described DONE documentation work
from a prior autonomous-continuation session (pre-2026-04-21 cutoff).
The work it summarises is already reflected in ADVANCED_FEATURES.md,
DEPLOYMENT.md, PERFORMANCE.md, etc.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath