Keep the iOS keyboard up on a second tap of the token field

[Yoonwoo-Ha]

Summary

On an iPhone, tapping the token field a second time (to get the Paste menu) closed the keyboard.

Cause. lib/viewport.ts scrolls the page back to (0, 0) on every visual-viewport resize and scroll. It is meant to keep the shell's header and key bar on screen, but it also ran on the token gate. iOS scrolls a focused field into view when the keyboard opens, and again when the field is tapped. The page jumped back each time, so the second tap landed outside the field. A tap outside the field blurs it, and the keyboard closed.

Fix.

• Only the shell (.app) is pinned to the top now. The gate is left alone.
• The gate sizes itself to the visible height (--app-height, the value viewport.ts already sets). That centres the card above the keyboard, so iOS has nothing to scroll.

Two files changed, 9 lines added. Independent of #5 and #6.

Testing

• bun run typecheck passes and bun test passes 252/252 on main.
• In headless Chrome with the iPhone 13 device profile, against a token-protected test server:
  • While the gate shows, window.scrollTo is never called, even after the viewport shrinks as it would for a keyboard.
  • A second tap keeps the field focused.
  • The gate fills the visible height, and the field sits inside it.
  • After unlocking, the shell is still pinned when the viewport resizes.
• The iOS keyboard itself can't be emulated. The WebKit check did not run because the installed WebKit build doesn't match playwright-core.

🤖 Generated with Claude Code