Make the double tap a stance that holds the net

Oliver on v376: "wenn man doppeltippt, geht er minimal vor". His own
ball's flight covered 4-9 m of the 10 to the net. His next ball was met
from mid-court, outside the net zone, and the recovery after that volley
walked him straight back to the baseline.

The double tap now sets a stance (P.post) that lasts until the next
double tap, a lob he has to run down, or the end of the point. Every
recovery heads for the net at full pace, and every incoming ball is
planned as a net man's. The 'back' stance clears once he is behind the
net zone, so short balls still pull him in.

Measured: contacts while committed are ~35% at the net and ~40% around
the service line, and he no longer falls back. The base ladder is
unchanged. New test; v377.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/state.js

@@ -207,7 +207,7 @@ export const other = s => s === 'P' ? 'O' : 'P';
 export const deuceSide = () => (score.pts[0] + score.pts[1]) % 2 === 0; // even points → deuce (right) side
 
 export function setupPoint() {
-  G.phase = 'pretoss'; ball.active = false; ball.bounces = 0; ball.scored = false; ball.rx = null; ball.heels = 0; P.chase = P.goal = P.goalKey = null; P.running = false; ball.approach = null; ball.retreat = null; ball.smash = false;
+  G.phase = 'pretoss'; ball.active = false; ball.bounces = 0; ball.scored = false; ball.rx = null; ball.heels = 0; P.chase = P.goal = P.goalKey = P.post = null; P.running = false; P.rushing = false; ball.approach = null; ball.retreat = null; ball.smash = false;
   G.swingSnaps = null; G.rallyNear = null; G.swung = false;
   if (G.mode === 'splatter' && !G.match) { // always your serve, from wherever you're standing
                                            // (the MATCH falls through to the tennis branch below: