feat: update external success screen text and image

[jvsena42]

FIGMA

This PR:

1. Updates the external success screen title from "Connection initiated" to "Channel opening"
2. Replaces the switch box image with a lightning bolt illustration
3. Adds a dedicated "Spending Balance" nav title for the success screen
4. Translates all new and updated strings across 15 locales

Description

Updates the external node connection success screen to match the new Figma design. The title now reads "Channel Opening" (with "Opening" accented in purple), the illustration is a lightning bolt, and the nav bar shows "Spending Balance" instead of the shared "Lightning Connection" title.

Preview

QA Notes

Flow 1: Manual External Node Setup

1. From Home, tap the Lightning suggestion card (or navigate to Transfer Intro > Continue)
2. On the "Fund your spending balance" screen, tap Advanced
3. On the "Advanced setup" screen, tap Manual Setup
4. Complete the external connection flow (enter node URI, set amount, confirm)
5. Verify the success screen shows:
   • Nav title: "Spending Balance"
   • Title: "Channel" on line 1, "opening" on line 2 in purple
   • Lightning bolt illustration (not the old switch box)
   • Description text unchanged

manual.webm

Flow 2: LNURL Channel (QR Scan)

1. From the "Advanced setup" screen, tap Scan LNURL
2. Scan a valid LNURL-channel QR code
3. Confirm the connection
4. Verify the same success screen appears with the updated design

[claude]

Code review

Found 2 issues.

[jvsena42]

Still fixing my setup to record lnurl channel test

[ovitrif]

Used cherry-pick to port the fix described here, because the original PR where I fixed it wasn't targeting master directly:

• feat: add transfer from savings button on empty spending screen #882 (comment)

[ovitrif]

tAck

Updates I did:

• Ported the fix for the secondary button size so the fix lands into master earlier, previous fix I did was on PR #882 which is stacked on a draft PR. (merging should not be such a big pain as I simply cherry-picked the commits 🤞🏻 )
• updated the changelog entry to be more "public-facing" friendly

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For testing, I compared vs. Figma:

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PRO tip: You can open a channel manually to the LSP node, making it the easiest flow to test these design updates.

Flow steps:

• Drawer > App Status > LN Node > Scroll & tap trusted peer card to copy > back
• Lightning Connections > Add > Advanced > Manual Setup > Paste Node URI

Warning: note that you won't be able to send LN from another mobile device to this channel, so better close it right after.