Build: make Android build work behind restrictive proxies

- settings.gradle.kts: comment out the foojay-resolver-convention plugin.
  It tries to auto-download JDK toolchains from api.foojay.io, which fails
  with 503 behind restrictive proxies. Re-enable at home if you want
  auto-provisioning.
- app/build.gradle.kts: comment out jvmToolchain(17) for the same reason
  (triggers toolchain resolution -> foojay download). The build JDK 21
  plus compileOptions(source/target 17) achieves the same result locally.
- gradle-wrapper.properties: bump to gradle-9.6.1-all (matches the
  manually provided distribution).
- .gitignore: ignore .ssl-work/ (local corporate-CA truststore).

android/settings.gradle.kts

@@ -26,7 +26,11 @@ dependencyResolutionManagement {
 }
 
 plugins {
-    id("org.gradle.toolchains.foojay-resolver-convention") version "1.0.0"
+    // The foojay-resolver-convention auto-downloads JDK toolchains from
+    // api.foojay.io if a configured toolchain is missing. Behind restrictive
+    // proxies this download fails (503), so we rely on a locally installed
+    // JDK instead. Re-enable at home if you want auto-provisioning.
+    // id("org.gradle.toolchains.foojay-resolver-convention") version "1.0.0"
 }
 
 rootProject.name = "Mitbringsl"