restore spawn-phase glow with a true breathing animation

SpawnOverlayPass had everything wired except a caller. WebGLFrameBuilder
now collects spawned human players each tick during spawn phase and
pushes their territory centroid + color through view.updateSpawnOverlay.
myPlayer reads as white so the local-player ring stands out.

Reshaped the shader animation: dropped the growing-disc effect, gave
the ring a true breath — radius scales 0.5×→1.15× while opacity pulses
35%→100% in phase. Replaced the sharp inner-edge ramp with a smooth
center-to-boundary fill so there's no hard cutoff or empty hole in
the middle. animSpeed bumped to 0.0035 (~1 breath/sec).

src/client/render/gl/render-settings.json

@@ -245,7 +245,7 @@
     "selfMaxRad": 24,
     "mateMinRad": 5,
     "mateMaxRad": 14,
-    "animSpeed": 0.005,
+    "animSpeed": 0.0035,
     "gradientInnerEdge": 0.01,
     "gradientSolidEnd": 0.1
   },