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/gradle/wrapper/gradle-wrapper.properties

@@ -1,7 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.1.0-bin.zip
-distributionSha256Sum=a17ddd85a26b6a7f5ddb71ff8b05fc5104c0202c6e64782429790c933686c806
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.6.1-all.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME