home: a search's pointer previews the match under it, and leaving gives the card back to the cursor

[AbirAbbas]

Found by the real-model tmux suite after the senior-dev wave. TestTUIE2E/hover_previews_the_match_under_the_pointer fails on dev, and it is the only failure there that is the product rather than the suite (see #1540).

What a person saw. At 180 columns, typing Seed on Home lists the three matches. Pointing at Seed Beta drew nothing to the right of the list. The manual promises "a card … about the match under the cursor — or the one under your pointer while it is on one".

Why. Since #1071 (17ae56d34), the card has read only the keyboard cursor, and a hover moved that cursor. A redraw could hand the cursor back to the start a new conversation row, whose card is deliberately empty. Leaving the list could never restore the cursor's match, because the hover had overwritten it.

Now. While a search is typed:

• The pointer previews the match under it and leaves the keyboard cursor where the keys put it.
• Moving off the matches gives the card back to the cursor's match.
• The card's own chords (→, ctrl+o, ctrl+y, …) act on the card on screen.
• Any other key retires the hover, so enter and typing still act on the cursor.

Resting Home keeps #1071's single selection. A folder gone match still gets a card, and the manual now says so.

Proof.

• TestHomeSearchCardFollowsKeyboardCursor, …FollowsPointerMatch, …ReturnsToCursorWhenPointerLeaves and TestHomeSearchHasNoSideCardBelow136Columns are written from the manual section, and each fails on the old code.
• The real-binary subtest fails on the old binary (no card for Seed Beta) and passes on this one (Seed Beta's card on the right, then back to the cursor's card when the pointer leaves).
• make pr-ready is green, including internal/tui3's full sharded suite.

🤖 Generated with Claude Code