chore: update Home Assistant version to 2026.5.3

Updates config/.HA_VERSION and ha-version-badge.svg to Home Assistant 2026.5.3.

config/.HA_VERSION

@@ -1 +1 @@
-2026.4.4
+2026.5.3

ha-version-badge.svg

@@ -1,5 +1,5 @@
-<svg width="61.5" height="20" viewBox="0 0 615 200" xmlns="http://www.w3.org/2000/svg" role="img" aria-label="2026.4.4">
+<svg width="61.5" height="20" viewBox="0 0 615 200" xmlns="http://www.w3.org/2000/svg" role="img" aria-label="2026.5.3">
-  <title>2026.4.4</title>
+  <title>2026.5.3</title>
   <linearGradient id="sqZjf" x2="0" y2="100%">
     <stop offset="0" stop-opacity=".1" stop-color="#EEE"/>
     <stop offset="1" stop-opacity=".1"/>
@@ -10,7 +10,7 @@
     <rect width="615" height="200" fill="url(#sqZjf)"/>
   </g>
   <g aria-hidden="true" fill="#fff" text-anchor="start" font-family="Verdana,DejaVu Sans,sans-serif" font-size="110">
-    <text x="65" y="148" textLength="500" fill="#000" opacity="0.25">2026.4.4</text>
+    <text x="65" y="148" textLength="500" fill="#000" opacity="0.25">2026.5.3</text>
-    <text x="55" y="138" textLength="500">2026.4.4</text>
+    <text x="55" y="138" textLength="500">2026.5.3</text>
   </g>
-</svg>
+</svg>