Add Houdini private-send prototype scene (Proposal A)

Adds a review-only, fully navigable prototype of the redesigned Houdini
private send flow, reachable from a wallet's Send button. The scene
reorganizes the send-to-address experience with two linked amounts
(You send / Recipient gets) computed from a hard-coded rate, a
recipient-asset picker over a hard-coded chain list, a Private send
toggle, an inline quote row, a network fee row, and a conditional
destination-tag row. Cross-asset or private sends complete on
SwapSuccessScene; same-asset sends show the transaction success modal.
Nothing talks to Houdini; all values are hard-coded. The card grouping
uses Proposal A (From -> To grouping).

Author: j0ntz

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased (develop)
 
+- added: Houdini private-send prototype scene (Proposal A) reachable from a wallet's Send button, with hard-coded linked amounts, a recipient-asset picker, a Private send toggle, and modal vs swap-success completion paths.
 - added: Remote enable/disable of gift card providers via the info server's giftCardInfo config, supporting whole-provider disabling for Phaze and Bitrefill and per-brand disabling for Phaze.
 
 ## 4.49.0 (staging)

src/components/Main.tsx

@@ -106,6 +106,7 @@ import {
 } from './scenes/GuiPluginListScene'
 import { GuiPluginViewScene as GuiPluginViewSceneComponent } from './scenes/GuiPluginViewScene'
 import { HomeScene as HomeSceneComponent } from './scenes/HomeScene'
+import { HoudiniSendScene as HoudiniSendSceneComponent } from './scenes/HoudiniSendScene'
 import { LoanCloseScene as LoanCloseSceneComponent } from './scenes/Loans/LoanCloseScene'
 import { LoanCreateConfirmationScene as LoanCreateConfirmationSceneComponent } from './scenes/Loans/LoanCreateConfirmationScene'
 import { LoanCreateScene as LoanCreateSceneComponent } from './scenes/Loans/LoanCreateScene'
@@ -242,6 +243,7 @@ const FioStakingChangeScene = ifLoggedIn(FioStakingChangeSceneComponent)
 const FioStakingOverviewScene = ifLoggedIn(FioStakingOverviewSceneComponent)
 const GuiPluginViewScene = ifLoggedIn(GuiPluginViewSceneComponent)
 const HomeScene = ifLoggedIn(HomeSceneComponent)
+const HoudiniSendScene = ifLoggedIn(HoudiniSendSceneComponent)
 const GiftCardAccountInfoScene = ifLoggedIn(GiftCardAccountInfoSceneComponent)
 const GiftCardListScene = ifLoggedIn(GiftCardListSceneComponent)
 const GiftCardMarketScene = ifLoggedIn(GiftCardMarketSceneComponent)
@@ -1087,6 +1089,7 @@ const EdgeAppStack: React.FC = () => {
         options={{ headerShown: false }}
       />
       <AppStack.Screen name="send2" component={SendScene2} />
+      <AppStack.Screen name="houdiniSend" component={HoudiniSendScene} />
       <AppStack.Screen
         name="debugSettings"
         component={DebugScene}