Feature/settings redesign

[theperu]

🎯 Description

Refactors the Settings section to use a consistent page layout pattern across all sub-pages. Previously, several settings pages had a custom in-body header (a circle icon + large title text inside a Padding widget) alongside inconsistent AppBar styling. This PR standardises all pages to use the AppBar title property and aligns padding/scroll physics with the rest of the app.

Additionally, the Settings main page gains a social links footer, and the Collaborators page is fully redesigned with a card-based list, platform icons, and a GitHub CTA.

Closes: # (issue)

📱 Changes

• All settings sub-pages: Removed custom in-body headers; page titles moved to AppBar's title property
• All settings sub-pages: Standardised body top padding to EdgeInsets.only(top: Sizes.xl) and added BouncingScrollPhysics where missing
• backup_page.dart: Removed manual AppBar overrides (backgroundColor, elevation, centerTitle, custom titleTextStyle), now inherits from the app theme
• settings_page.dart: Converted body from SingleChildScrollView + nested ListView to a single ListView.builder; moved the developer-options GestureDetector to the AppBar title; added a bottomNavigationBar footer with social links (GitHub, LinkedIn, YouTube, Discord)
• collaborators_page.dart: Converted to ConsumerWidget, extracted a _ContributorCard widget, added a "Meet the team" header, platform-aware icons (font_awesome_flutter), and a GitHub contribution CTA card
• pubspec.yaml: Added font_awesome_flutter: ^10.12.0 as a direct dependency

🧪 Testing Instructions

Behaviour

1. Navigate to Settings, confirm the page title appears in the AppBar and there is no large icon/title header inside the body
2. Confirm the bottom of the Settings page shows social link icon buttons (GitHub, LinkedIn, YouTube, Discord)
3. Tap the "Settings" title in the AppBar four times quickly to verify the developer options banner still activates
4. Open each sub-page (General Settings, Accounts, Categories, Import/Export, Notifications, App Info) and confirm each has a standard AppBar title with no in-body header
5. Open App Info → Collaborators, confirm the redesigned card list renders with correct names, roles, and platform icons; tap a card to confirm it opens the correct URL
6. Confirm the GitHub CTA card at the bottom of the Collaborators page opens https://github.com/RIP-Comm/sossoldi
7. On the Import/Export page, tap "Import data" and confirm the warning dialog appears; tap "Export data" and confirm the export flow runs

📸 Screenshots / Screen Recordings (if applicable)

Settings.redesign.mp4

🔍 Checklist for reviewers

• Code is formatted correctly
• Tests are passing
• New tests are added (if needed)
• Style matches the figma/designer requests
• Tested on:
  • iOS
  • Android

[federicopozzato]

Looks great to me

[theperu]

@lucaantonelli I also pushed another fixed that we had missed with the subcategories. Basically if we changed the color of the main category the subcategories didn't update