[FEATURE]: Scroll line-by-line like Vim ctrl-e and ctrl-y

[NathanFlurry]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Vim provides ctrl-e and ctrl-y scroll line-by-line behavior. Would be nice for OpenCode to support this.

Biggest motivation here is that OpenCode does not play nice with tmux scrollback, so all of the scroll keybindings that vim users are used to need to be replicated.

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Feature: opencode CLI uses fixed input + scrollable output pane, breaks Neovim-style scrolling #8600: Feature: opencode CLI uses fixed input + scrollable output pane, breaks Neovim-style scrolling
• Scroll speed is super fast in the Antigravity CLI #8242: Scroll speed is super fast in the Antigravity CLI
• Scroll not working #8449: Scroll not working

These issues are related to scrolling functionality in OpenCode. While your request is specifically for vim ctrl-e/ctrl-y keybinds, these issues may provide additional context on scrolling challenges within the TUI.

For keybind-related issues, please also check our pinned keybinds documentation: #4997