Fix overflowing single-line input scrolling

[kvnwdev]

Summary

• clip overflowing single-line input text to its viewport
• retain horizontal scroll offsets and follow the active caret
• preserve textarea vertical scrolling and text state across view rebuilds

Root cause

Single-line fields advertised clipped overflow, but their display list emitted no clip command and their text origin ignored retained scroll state. Long values could paint beyond the field and move the caret out of view.

Validation

• scripts/gate.sh fast
• NATIVE_SDK_PATH=~/code/native NATIVE_SDK_ZIG=$(command -v zig) native test in ~/code/native-app-testing (16/16)
• live notes-app automation with a 32-byte collection name: full value retained, oldest glyphs clipped left, caret visible at the right edge, adjacent note count fixed in place

[vercel]

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[ctate]

Hey @kvnwdev - really appreciate the PR and for tracking down the root cause. It helped us fix this issue, along with a couple of related ones in #90.

I added you as a co-author on that PR. Thanks for your help!