chore: promote dev to main

[Chefski]

Summary

Promote the complete dev branch to main to trigger a new Xcode Cloud build.

This includes:

• CRDT-native offline document editing
• page discovery and navigation improvements
• editor author bylines
• page card overflow spacing adjustment
• the TestFlight download badge in the README

Validation

• origin/dev is clean and aligned with local dev at 6ba18bd
• git diff --check passed
• SwiftLint strict mode passed for all changed Swift files

Xcode builds and tests were not run locally, per repository instructions.

[greptile-apps]

Too many files changed for review. (242 files found, 100 file limit)

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