feat: mobile-first wiki UX improvements

[alexk-dev]

Summary

• Reworked the top toolbar for mobile-first usage: primary actions stay visible and secondary actions move into an overflow menu.
• Improved the editor on small screens with a fixed bottom action bar for metadata, close, and save actions.
• Constrained document metadata sections and version history so long link/history lists do not grow the page indefinitely.
• Fixed first-line offset in rendered code blocks and corrected root page editing via /e.
• Reloaded spaces after auth state resolves so the account menu can switch spaces immediately after login.