chore: archive completed implementation plans

Move 6 fully-implemented plans to docs/plans/archive/:
- radical-refactor (design + impl): ese-test-fixtures, crate unification
- steal-features: CSV, connectivity/energy/notifications/timeline tables
- comprehensive-srum-features: 14-task forensicnomicon heuristics + sr-cli expansion
- srum-analysis-refactor (design + impl): 11-task pipeline DRY refactor

Active plans (GUI) remain in docs/plans/.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: h4x0r