feat(portfolio): add expanded layout for bond position cards

Add variant="bond" to PositionCard with bond-specific CSS classes
(.bondCard, .bondMain, etc.) matching the stock expanded layout.
PositionSection now passes variant based on section kind.
Bond cards render 3-column grid (logo | identity | value) with
meta row, identical to stock cards.

scripts/lazy-route-bundle-baseline.json

@@ -2,7 +2,7 @@
 	"src/app/routes/ProtectedLayout.tsx": 3057,
 	"src/pages/account-events/index.ts": 4364,
 	"src/pages/account-operations/index.ts": 13854,
-	"src/pages/account/index.ts": 24695,
+	"src/pages/account/index.ts": 25407,
 	"src/pages/accounts/index.ts": 6145,
 	"src/pages/login/index.ts": 662,
 	"src/pages/not-found/index.ts": 877,