docs: archive completed design docs (#398, #401) to processed/ (#452)

Both issues are COMPLETED — move their design docs from docs/designs/ to docs/processed/ per PRD triage policy. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Juan Manuel Servera committed Jun 13, 2026 at 16:23 UTC ba21737f0a21b1ccdb1d7f98dd9c9ac49055ddaf
2 files changed
docs/processed/398-month-synthesis.md renamed
docs/processed/401-historical-context.md renamed