Roster: strain_id format inconsistent between rows; plant editor forces plant_name == nickname

PARTIAL FIX 2026-09-06 (code landed, unverified on live): new compose_ops.strain_slug() is now the single code path for strain_id on compose-create AND the plant editor’s PATCH (update_pot_recipe was storing the raw display string). New rows / edited rows get a consistent slug. Existing rows keep their current strain_id until next edit — a one-off backfill could normalise pot1. plant_name==nickname is intentional (the editor has one ‘Nickname’ field) — leave unless a real name/nickname split is wanted. — ORIGINAL: pot1 strain_id ‘Runtz Punch’ (raw) vs pot2 ‘grandmommy_purple’ (slug).