[iOS] New Onboarding UI refresh

[kylehickinson]

This alters the new "welcome focus" onboarding design to match the new refreshed version and implements the iPad column design.

This also updates the DesignSystem SwiftUI button styles to match the most up to date Figma designs (updated radius + minimum heights, updated colors in outline style)

Resolves brave/brave-browser#43883
Resolves brave/brave-browser#44184

Submitter Checklist:

• I confirm that no security/privacy review is needed and no other type of reviews are needed, or that I have requested them
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally:
  • npm run test -- brave_browser_tests, npm run test -- brave_unit_tests wiki
  • npm run presubmit wiki, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

• Set region to new onboarding available region (UK/JP), and install fresh
• Verify basic designs:

Designs: https://www.figma.com/design/FiluJhwOjucQL4iGLmVZLW/iOS-Onboarding?node-id=5107-8391
Figma Previews: https://www.figma.com/proto/FiluJhwOjucQL4iGLmVZLW/iOS-Onboarding?page-id=5107%3A8391&node-id=5160-20103&p=f&t=y2JeZPZxQaysKkJc-0&scaling=min-zoom&content-scaling=fixed&starting-point-node-id=5160%3A20102&show-proto-sidebar=1 (note the iPhone, iPad - Portrait, iPad - Landscape pages for different layouts)

• Verify multi-tasking on iPad still shows correctly
• Verify different font sizes render correctly

[Brandon-T]

nit: Might be more clear to explicitly use Array<any OnboardingStep>. But just a nit and can be ignored anyway.

[github-actions]

Chromium major version is behind target branch (133.0.6943.54 vs 134.0.6998.15). Please rebase.

[github-actions]

[puLL-Merge] - brave/brave-core@27605

Description

This PR significantly refactors the onboarding experience in the iOS Brave browser by introducing a new modular onboarding system. The changes replace the existing focus onboarding implementation with a more flexible and maintainable architecture using SwiftUI.

Changes

Changes

By file/component:

Onboarding Architecture:

• Introduced new OnboardingController and OnboardingRootView as core components
• Created an OnboardingStep protocol to standardize step creation
• Added environment variables for layout styles and dependencies
• Implemented responsive layouts (fullscreen, inset, columnInset)

Onboarding Steps:

• Added BlockInterruptionsOnboardingStep
• Added DefaultBrowserOnboardingStep
• Added P3AOptInOnboardingStep
• Each step follows a consistent pattern with title, graphic and actions

UI Components:

• Added BraveAppIcon component
• Updated BraveButtonStyle with improved sizing and styling
• Added BraveOutlineButtonStyle
• New splash screen implementation

Asset Changes:

• Added new Brave wordmark SVG
• Updated background images
• Removed unused fonts (Poppins)
• Updated various image assets

Integration:

• Updated BrowserViewController to use new onboarding system
• Removed FocusOnboardingFonts registration
• Updated callout presentations

sequenceDiagram
    participant U as User
    participant BVC as BrowserViewController
    participant OC as OnboardingController
    participant OS as OnboardingStep
    
    U->>BVC: Launches App
    BVC->>OC: Creates OnboardingController
    OC->>OS: Initializes Steps
    OC-->>U: Shows Splash Screen
    U->>OS: Interacts with Step
    OS-->>OC: Reports Step Completion
    OC->>OS: Shows Next Step
    OS-->>U: Shows Completion
    OC-->>BVC: Dismisses Onboarding

Loading

Possible Issues

1. Region-specific onboarding flows might need additional testing as there are checks for isNewOnboardingRegion
2. Dynamic type and accessibility support should be thoroughly tested across all new components
3. The splash screen animation timing might need adjustment based on device performance

Note: This appears to be a major refactor of the onboarding system, so thorough testing across different devices and configurations would be recommended before deployment.

[brave-builds]

Released in v1.77.66