Redesign Bridge screen UI to match Swap's modern card layout

Replaces the segmented pair/direction buttons and plain-text amount
sections with token-icon cards (BridgeAssetInputView), a one-tap flip
button, and a bottom-sheet pair picker (BridgePairListBottomSheet).
BridgeViewModel gains only additive presentation data (fromCard/toCard/
pairOptions, derived from the existing pair/direction state and the
same chainId/assetId mapping swapClicked() already used) - all bridge
business logic (rate, fee, minimum, liquidity warnings, submission)
is unchanged.

common/src/main/res/values/strings.xml

@@ -355,6 +355,8 @@
 
     <!-- Bridge Screen -->
     <string name="bridge_title">DOT ↔ HEZ Bridge</string>
+    <string name="bridge_pair_dot_hez">HEZ ⇄ DOT</string>
+    <string name="bridge_pair_usdt">USDT ⇄ USDT.p</string>
     <string name="bridge_you_send">You send</string>
     <string name="bridge_you_receive">You receive (estimated)</string>
     <string name="bridge_exchange_rate">Exchange rate</string>