fix: align onboarding slides layout with ios

[jvsena42]

This PR polishes the onboarding slides and Create Wallet screen to match the bitkit-ios layout.

Description

1. Caps the slide and Create Wallet image at 311x311 (was filling the full width), centered horizontally to match iOS
2. Replaces the Box + hardcoded padding(top = 125.dp) layout with a Column using a top weighted Spacer so the image is bottom-weighted like iOS
3. Sets the gap between image and title to 48dp (matching iOS padding(.top, 48)) and the title-to-body gap to 14dp (was 8dp)
4. Reserves a 255dp minimum height for the text block on each slide so there is breathing room above the page dots, matching iOS minHeight: 255
5. Styles the disclaimer with White32 and a 4dp top gap, matching iOS CaptionText
6. Removes the hardcoded 16dp bottom padding / 16dp height container around the dots so they sit at the bottom of the safe area like iOS
7. Keeps the existing active/inactive dot size animation (10dp vs 7dp) and the last-page fade-out transition

Preview

android.webm

ios.mp4

QA Notes

1. Launch a fresh onboarding flow and advance through slides 0, 1, 2
   • Verify each image is capped at 311x311dp and centered (not stretched full width)
   • Verify there is clear breathing room between the body text and the page dots at the bottom
   • Verify the title-to-body gap looks slightly larger than before
2. On Slide 1, confirm the disclaimer text (when geo-blocked) renders in White32 with a small gap below the body text
3. Verify the page dots
   • Active dot animates to ~10dp, inactive dots ~7dp
   • Dots sit at the bottom safe-area and are no longer pushed up by the old 16dp padding
   • On transition to the last page (Create Wallet), the dots fade and slide out
4. On the Create Wallet screen
   • Verify the wallet image is 311x311dp and centered
   • Verify the header + body copy spacing matches iOS (14dp between title and body)
   • Verify the 32dp gap before the Create / Restore button row and the 16dp bottom gap
   • Tap Advanced Setup in the top bar and confirm the passphrase flow still opens
5. Verify on a small device (e.g. NEXUS_5 preview) the layout still looks correct (image scales down, text block does not collide with dots)

[piotr-iohk]

LGTM, tested on "Small device" emulator. Looking good!

[claude]

Trailing comma on modifier = ... at a call site violates the CLAUDE.md rule:

NEVER add a trailing comma to modifier = ... at call sites

Context:

bitkit-android/app/src/main/java/to/bitkit/ui/onboarding/OnboardingSlidesScreen.kt

Lines 187 to 191 in 5a6c92a

	) {
	Column(
	modifier = modifier.fillMaxSize(),
	) {
	FillHeight()

Suggested change

	modifier = modifier.fillMaxSize(),
	modifier = modifier.fillMaxSize()