feat(airport): draw six equal apron fans instead of strip runways

Sectors are 60-degree wedges from the board centre, tucked against the tray. Radial seams mark the ABCDEF flats. Roll back with git checkout feat/airport-edge-runway.

labs/airport/README.md

@@ -8,7 +8,7 @@
 
 点击地面飞机起飞，点击场外停机坪上的飞机降落；左右转每次 60°。成功、失败与旋转都消耗一次。灰色轨道不分颜色；来机匹配彩色专用机位。P 标记表示已停好的来机。它再次起飞后，停到实际出口那条边的停机坪，仍需重新停好。
 
-板边轨道一直画到托盘外缘，不伸出棋盘。托盘外的浅色停机坪航线固定不动。当等待机在当前朝向下接得上同色机位时，盘内通道用中性强调色点亮；旋转时通道会亮灭，据此判断能否进场。
+板边轨道一直画到托盘外缘，不伸出棋盘。托盘外是以棋盘中心为焦点的六等分扇形停机坪，对应六条平边；扇形不随底盘旋转。当等待机在当前朝向下接得上同色机位时，提示线从飞机接到盘内通道；旋转时通道会亮灭，据此判断能否进场。
 
 ## 关卡证据
 

labs/airport/app.js

@@ -1,4 +1,4 @@
-import { AirportGame, SIDES, boardAt, catalogs, parkedCount, copy, boardRadius, waitingPose, apronDistance, trayHull, rimCrossing, bayNormal, TRAY_PAD } from './core.js';
+import { AirportGame, SIDES, boardAt, catalogs, parkedCount, copy, boardRadius, waitingPose, apronDistance, trayHull, rimCrossing, TRAY_PAD } from './core.js';
 import { LEVELS } from './levels.js';
 import { requestReward } from './rewards.js';
 import { position, PORTS, hexPoints, trackPoints, sweepPath } from '../../src/path-math.js';
@@ -22,7 +22,6 @@ try { const value = JSON.parse(localStorage.getItem(STORAGE)); if (value && Arra
 function persist() { try { localStorage.setItem(STORAGE, JSON.stringify(saved)); } catch {} }
 let index = Number.isInteger(saved.last) && saved.last >= 0 && saved.last < LEVELS.length ? saved.last : 0;
 let game, motions = [], rotation = null, feedback = null, queue = [], requestId = 0, diagnosis = null, generation = 0;
-const APRON_WIDTH = 1.9;
 let view = { width: 390, height: 460, size: 28, ox: 195, oy: 230 }, audioContext;
 const worker = new Worker(new URL('./solver-worker.js', import.meta.url), { type: 'module' });
 worker.onmessage = ({ data }) => {
@@ -242,6 +241,19 @@ function clipToHull(points,poly){
   }
   return out;
 }
+function apronSector(hull,side,outerR,steps=12){
+  const a0=-Math.PI/2+side*Math.PI/3,a1=a0+Math.PI/3,pts=[];
+  for(let i=0;i<=steps;i++){
+    const a=a0+(a1-a0)*i/steps,dir={x:Math.cos(a),y:Math.sin(a)};
+    const t=rimCrossing(hull,{x:0,y:0},dir),r=(t??0)+.08;
+    pts.push({x:dir.x*r,y:dir.y*r});
+  }
+  for(let i=steps;i>=0;i--){
+    const a=a0+(a1-a0)*i/steps;
+    pts.push({x:Math.cos(a)*outerR,y:Math.sin(a)*outerR});
+  }
+  return pts;
+}
 function aircraft(plane,where,alpha=1){
   ctx.save();ctx.translate(where.x,where.y);ctx.globalAlpha=alpha;
   const color=pigments[plane.color].color;
@@ -264,15 +276,16 @@ function draw(now){
   ctx.translate(view.ox,view.oy);ctx.scale(view.size,view.size);
   const board=rotation?rotation.old:catalogs(game.level)[game.state.orientation].board;
   const hullPts=trayHull(board.cells);
-  // Fixed apron slabs sit under everything: waiting planes park on a soft lane outside
-  // the tray, on each side's flat-side normal, so a plane's side is readable before any
-  // hint appears. They never turn with the base.
+  // Six equal apron fans, fixed around the board centre. They replace the old
+  // strip runways so each visual flat (the ABCDEF wedges) is a readable sector.
   const radius=boardRadius(game.level.cells),apronR=apronDistance(radius);
+  const stacks=Math.max(1,...[0,1,2,3,4,5].map(s=>game.level.arrivals.filter(a=>a.side===s).length));
+  const outerR=apronR+(stacks-1)*1.12+.85;
+  for(let side=0;side<6;side++)polygon(apronSector(hullPts,side,outerR),materials.shadowSoft);
   for(let side=0;side<6;side++){
-    const n=bayNormal(side),count=Math.max(1,game.level.arrivals.filter(a=>a.side===side).length);
-    const inner=rimCrossing(hullPts,{x:0,y:0},n)+0.20,outer=apronR+(count-1)*1.12+0.85;
-    if(!(outer>inner))continue;
-    line([{x:n.x*inner,y:n.y*inner},{x:n.x*outer,y:n.y*outer}],materials.shadowSoft,APRON_WIDTH);
+    const a=-Math.PI/2+side*Math.PI/3,dir={x:Math.cos(a),y:Math.sin(a)};
+    const t=rimCrossing(hullPts,{x:0,y:0},dir),inner=(t??0)+.08;
+    line([{x:dir.x*inner,y:dir.y*inner},{x:dir.x*outerR,y:dir.y*outerR}],materials.shadow,.045);
   }
   ctx.save();
   if(rotation){const p=Math.min(1,(now-rotation.start)/rotation.duration),u=p*p*(3-2*p);ctx.rotate(rotation.direction*Math.PI/3*u);}