fix: allow ArrowUp/ArrowDown/Space during filtering in multiselect

[gaojunran]

pitchfork relies on this fix!

[gemini-code-assist]

Code Review

This pull request enables navigation and item toggling within the filtering mode of the MultiSelect component. Feedback highlights a potential panic risk due to unclamped cursor indices when the filtered list size changes, and a UX conflict where using the Space key for toggling prevents multi-word search queries. It is recommended to use the Tab key for toggling and to ensure the cursor is properly clamped.

[greptile-apps]

Greptile Summary

This PR enables ArrowUp, ArrowDown, and the toggle key (defaulting to Space) during filtering in MultiSelect, and introduces a configurable toggle_key builder so callers can choose a different key when they need Space for filter queries.

• Navigation during filtering: handle_down/handle_up are now routed from the filtering match branch, and handle_toggle is reached when toggle_key is pressed while the filter is active.
• Stale-cursor safety: self.cursor is reset to 0 in both handle_filter_key and handle_filter_backspace so narrowing the list never leaves the cursor pointing past the visible results; handle_toggle also clamps with .min(visible_options.len().saturating_sub(1)) to guard against any remaining out-of-bounds access.
• Help text: The filtering-mode help bar now lists ↑/↓, the toggle key label, esc, and enter, so the new bindings are discoverable.

Confidence Score: 5/5

Safe to merge — all previously flagged defects are addressed and no new issues were found.

The stale-cursor bug, the out-of-bounds access in handle_toggle, and the missing help-text updates are all resolved in this diff. The toggle_key guard arm is correctly ordered ahead of the Char wildcard so Space interception works as designed. No regressions were found in the existing rendering or paging logic.

No files require special attention.

Important Files Changed

Filename	Overview
src/multiselect.rs	Adds ArrowUp/ArrowDown/Space navigation during filtering, configurable toggle_key, cursor-reset on filter change, OOB-safe handle_toggle, and updated help text — all previous P1 issues resolved

_{Reviews (5): Last reviewed commit: "fix(multiselect): support filtering navi..." | Re-trigger Greptile}

[gaojunran]

@greptileai

[gaojunran]

@greptileai