feat(interests): CM-2 Part B — interest_berths price override (data + resolver)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/db/schema/interests.ts

@@ -165,6 +165,10 @@ export const interestBerths = pgTable(
     addedBy: text('added_by'),
     addedAt: timestamp('added_at', { withTimezone: true }).notNull().defaultNow(),
     notes: text('notes'),
+    // CM-2 Part B: deal-specific price for THIS (interest, berth). Null = use
+    // the berth's canonical list price. Does not touch berths.price.
+    priceOverride: numeric('price_override'),
+    priceOverrideCurrency: text('price_override_currency'),
   },
   (table) => [
     uniqueIndex('idx_ib_interest_berth').on(table.interestId, table.berthId),