feat(mobile): enhance Content tab editing UX with collapsible nav and bottom toolbar (#2030)

[shubhiscoding]

Issue: #2030

Description

• Add mobile-optimized editing experience for the Content tab with collapsible navigation, repositioned toolbar, and streamlined header
• Enable version selector dropdown on mobile devices during content editing
• Implement keyboard-aware toolbar positioning for better accessibility

Test plan

• [ ] On mobile browser, navigate to Products → Edit → Content tab
• [ ] Tap into the rich text editor to start editing
• [ ] Verify the navigation bar hides and a compact header appears with:
  • Back arrow (←) to exit editing mode
  • Product title centered
  • Save button and overflow menu (⋯) on the right
• [ ] Verify the Product/Content/Share tabs remain visible below the header
• [ ] Verify the version selector ("Editing: Version X") dropdown is visible and functional
• [ ] Verify the formatting toolbar appears fixed at the bottom, above the keyboard
• [ ] Tap the back arrow to exit editing mode
• [ ] Verify the navigation bar reappears and the layout returns to normal
• [ ] Test on desktop to ensure no regression (toolbar stays at top, nav always visible)

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Test Results

https://github.com/user-attachments/assets/567d836b-46d4-4e95-b07a-09591fbad41c

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Checklist

• [ ] I have read the contributing guidelines
• [ ] I have watched Gumroad PR review livestreams
• [ ] I have performed a self-review and left review comments on my PR
• [ ] I have added/updated tests for my changes

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AI Disclosure

Used Claude code to navigate understand codebase

[shubhiscoding]

@ershad attempted the fix as per the new UI redesign mentioned in the comment pr is ready for review! let me know if any change is required!

[binary-koan]

Thanks for exploring this, but looking at the custom event handling I think it's best we revisit it once the product edit page is in Inertia (#856). In the meantime I'll confirm in the issue whether we want to go with this design (you'd be very welcome to open a migration PR or rework this once someone else has migrated it!)

[shubhiscoding]

Thanks for exploring this, but looking at the custom event handling I think it's best we revisit it once the product edit page is in Inertia (#856). In the meantime I'll confirm in the issue whether we want to go with this design (you'd be very welcome to open a migration PR or rework this once someone else has migrated it!)

Hii @binary-koan have dropped pr for product edit page migration #2624 would like your review, and maybe then I can rework on this one!