fix: suppress deprecation and unchecked cast warnings in Quartz internal code

Deprecated APIs in Quartz are kept for library consumers but internal usages
now carry @Suppress annotations so the module builds warning-free. Also
replaces redundant .toInt() on hex Int literals in ChaCha20Core and migrates
deprecated java.net.URL to URI.resolve() in ServerInfoParser.

The spotless license header delimiter is updated to recognize @file: annotations.

https://claude.ai/code/session_01EwS56YAGGnnac5EuwhaUSs

quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip96FileStorage/info/ServerInfoParser.jvmAndroid.kt

@@ -21,7 +21,6 @@
 package com.vitorpamplona.quartz.nip96FileStorage.info
 
 import java.net.URI
-import java.net.URL
 
 actual fun makeAbsoluteIfRelativeUrl(
     baseUrl: String,
@@ -32,7 +31,7 @@ actual fun makeAbsoluteIfRelativeUrl(
         if (apiUrl.isAbsolute) {
             potentiallyRelativeUrl
         } else {
-            URL(URL(baseUrl), potentiallyRelativeUrl).toString()
+            URI(baseUrl).resolve(potentiallyRelativeUrl).toString()
         }
     } catch (e: Exception) {
         potentiallyRelativeUrl