Kill-All Go

[samtcifihi]

Adds Kill-All Go, a Go variant with asymmetric goals: the Attacker starts with stones on the
board and must capture everything, while the Defender wins by making one string that can never
be captured. There is no scoring. Flagged experimental. Boards are 9x9, 13x13 and 19x19.

Rules

Stones are placed and captured under Tromp-Taylor clearing, so multi-stone suicide is legal.
Positional superko applies across every position reached, including the intermediate positions
inside a multi-stone ply, which also makes single-stone suicide illegal. Two consecutive passes
end the game as an Attacker win.

The Defender wins the moment one of their strings is pass-alive by Benson's algorithm. Because
suicide is legal here, the vital-region test is the strict one: every point of a region must
touch the chain, not only its empty points, since the Attacker can otherwise clear its own
stones out of a region and refill it leaving a hole that is not a liberty.

Life in seki is claimed manually rather than detected. Instead of moving, the Defender names one
of their strings and any number of empty protected points. The Attacker then plays any number of
consecutive stones, none on a protected point. Capturing the string wins; ending the sequence on
a protected point resumes normal play with the Defender to move; submitting anything else gives
the claim up and loses. Life in ko is not recognised.

lightvector/goscorer was evaluated for automatic seki detection and rejected as a win
condition: its own documentation says eye values are not tactically accurate outside finished
positions, and a Kill-All claim is decided mid-game.

Openings

A single radio group. Alternating placement is the default: players take turns placing Attacker
stones until one takes the Attacker side, and the other then moves first as the Defender. The
handicap form adds a count chosen by Player 1, who should be seated first as the stronger
player. The classic form is the traditional 17-stone position, 19x19 only. There is a simple pie,
and a generalized form of Hoctaph's pie where the slicer chooses two batch sizes. Every protocol
keeps strict alternation, so the game is a plain GameBase, and the Defender always makes the
first normal move.

Seats are not colours. getPlayerColour returns a neutral grey until a side has been chosen, and
every user-facing string says Attacker and Defender rather than naming a colour.

Interface

Fixed choices are custom buttons; anything involving stones is clicked on the board, which is
unambiguous in each phase. The Hoctaph slice offers an on-board picker of numbered stones for the
sizes worth a single click, shading the values the other size forbids while leaving them
clickable. Larger sizes are still typed, and only a,b is ever stored.

Depends on

The button labels resolve from apfront.json, so this needs AbstractPlay/front PR (link) first,
or the buttons render their raw keys.

Testing

npx mocha passes. The game's own 61 tests cover the board mechanics, ten Benson fixtures in
both vital-region modes, every branch of every opening, superko, the claim protocol, end
conditions, the structured move log and serialization in each phase. Rendered JSON was validated
against the renderer schema for every phase.

check-game-names-locale reports names.killallgo missing from the machine-managed locales,
which is expected for a new game. Only en and eo are touched here.