TUI leaves stale "ghost" characters on screen in Termux, only cleared by forced full redraw

Description

On Termux (Android), during normal opencode TUI usage, leftover/duplicated text fragments remain visible on screen after content updates — they are not present in the actual output stream (confirmed by cloning and inspecting logs; PTY data is clean). The artifacts disappear only when the terminal is forced to fully redraw — e.g. rotating the screen (which triggers a resize/WindowSizeMsg). This strongly suggests the Bubbletea (v2) standard renderer's line-diffing doesn't fully erase the previous line before writing shorter new content in this terminal environment, possibly due to a character-width mismatch (icons/Nerd Font glyphs/emoji) between what Bubbletea assumes and how Termux's terminal-view renders them.

Repro:

1. Run opencode in Termux
2. Trigger UI updates where line length shrinks
3. Observe leftover/ghost characters
4. Rotate the screen → artifacts clear (full redraw via WindowSizeMsg)

Additional context:

• opencode TUI is built on Go + Charmbracelet Bubbletea (v2)
• Bubbletea's standard (non-alt-screen) renderer only diffs and overwrites changed lines rather than clearing the full screen
• Screen rotation changes terminal size → triggers WindowSizeMsg → full clear + redraw
• Related project that may have seen similar issues: wallentx/opencode-termux

Plugins

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OpenCode version

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Steps to reproduce

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Screenshot and/or share link

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Operating System

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Terminal

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