fix: prevent StringIndexOutOfBoundsException in Url.getPart()

When UrlDetector.readEnd() trims the last character from URLs ending
with characters like '.', ',', etc., the urlMarker indices remain
based on the original buffer length. This caused getPart() to call
substring() with an end index beyond the trimmed URL's length.

Fix by clamping the end index to originalUrl.length and guarding
against an out-of-bounds start index.

https://claude.ai/code/session_014Q2SvTE5vKgUm1w8dPVjYo

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/urldetector/Url.kt

@@ -228,11 +228,17 @@ class Url(
             return null
         }
 
+        val startIndex = urlMarker.indexOf(part)
+        if (startIndex < 0 || startIndex >= originalUrl.length) {
+            return null
+        }
+
         val nextPart = nextExistingPart(part)
         return if (nextPart == null) {
-            originalUrl.substring(urlMarker.indexOf(part))
+            originalUrl.substring(startIndex)
         } else {
-            originalUrl.substring(urlMarker.indexOf(part), urlMarker.indexOf(nextPart))
+            val endIndex = urlMarker.indexOf(nextPart)
+            originalUrl.substring(startIndex, minOf(endIndex, originalUrl.length))
         }
     }