Task: Show market_tier and monetary_nature as badge columns on the currency list by default

Once task AEEDE877 lands badge rendering for the market_tier and monetary_nature dynamic combos on the detail dialog, extend the same badge rendering to the currency list window's grid columns for these two fields, and ensure both columns ship visible by default (not hidden behind the column-visibility picker) — matching how Book's book_status column renders as a badge and is on by default in its list view. Blocked on AEEDE877's badge mechanism (dynamic-combo badge support doesn't exist yet); do not start before that lands.

• Currency list grid shows market_tier and monetary_nature as colour-coded badge pills, not plain text, matching Book's book_status badge column visually.
• Both columns are visible by default when the list window first opens for a user with no saved column-visibility preferences (not toggled on manually via the column picker).
• Existing users' saved column-visibility preferences aren't silently overridden if they'd previously hidden these columns on purpose.
• Build passes; verified live, not just by code inspection.

(Implementation strategy. Written when work starts; key decisions are distilled into the parent story's * Decisions at close, but the plan itself stays — it is the historical record of what we did.)

Done, but never marked as such. badge_key/is_badge are set for both monetary_nature and market_tier, in both the detail-dialog combos and the list-window columns (currency.org's * Detail fields and