make watchlist fully manual; add price + day-change, two-block overview

Per design decision: the watchlist is now purely user-curated (no auto-seeding
of the top-10), so the auto_populate/dismissed machinery is removed and removals
are plain deletes. Each entry is enriched with latest close + day-over-day move.

Overview now shows two clear blocks: Top Setups (what to trade) and My Watchlist
(my names with current price and today's %). Market watchlist table drops the
now-meaningless auto/manual Type column in favour of Price and Day columns.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/types.ts

@@ -20,6 +20,9 @@ export interface WatchlistEntry {
   rr_ratio: number | null;
   rr_direction: string | null;
   sr_levels: SRLevelSummary[];
+  last_close: number | null;
+  change_pct: number | null;
+  price_date: string | null;
   added_at: string;
 }