Bind carriage return alongside enter on the TUI board

[bjohas]

Fixes #1003

The board registers its Enter handler as screen.key(["enter"], ...) (src/ui/board.ts). In the vendored blessed fork (neo-neo-bblessed/lib/keys.ts), a carriage return is named return and only a linefeed is named enter:

if (s === '\r') {
  // carriage return
  key.name = 'return';
} else if (s === '\n') {
  // enter, should have been called linefeed
  key.name = 'enter';
}

Terminals that send CR for the Enter key — kitty on Linux among them — therefore reach no handler at all.

That handler does double duty: in move mode it confirms a pending move, and outside move mode it opens the task popup. On an affected terminal both silently do nothing.

The move case is especially opaque because performTaskMove swallows every error unless DEBUG is set, so a move that never fired is indistinguishable from one that failed. m still works as a confirm key, which makes the Enter path look selectively broken rather than unbound.

Fix

Bind both names. Added as an exported BOARD_ENTER_KEYS constant so it can be asserted in a test — the board needs a tty to instantiate, and the file already exports hasMoveBlockingBoardFilters / shouldRebuildColumns for the same reason.

screen.key(["enter"]) is the only such registration under src/ui/, and nothing registers "return" anywhere, so this is a single-site change.

Verification

• Reproduced and confirmed fixed on kitty / Ubuntu: Enter now both opens the task popup and confirms a pending move.
• bunx tsc --noEmit clean
• biome check clean on both files
• bun test src/test/board-ui.test.ts — 8 pass / 0 fail