Rename app to Castarr (dev.castarr.tv), add JDK toolchain resolution

Package/applicationId com.nodecast.tv -> dev.castarr.tv, all branding in app
and remote page renamed, remote localStorage key changed. Foojay toolchain
resolver + jvmToolchain(17) so hosts with only a JRE can build.

Closes #1

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/build.gradle.kts

@@ -4,11 +4,11 @@ plugins {
 }
 
 android {
-    namespace = "com.nodecast.tv"
+    namespace = "dev.castarr.tv"
     compileSdk = 35
 
     defaultConfig {
-        applicationId = "com.nodecast.tv"
+        applicationId = "dev.castarr.tv"
         minSdk = 23
         targetSdk = 35
         versionCode = 1
@@ -32,6 +32,7 @@ android {
         allWarningsAsErrors = true
     }
 
+
     lint {
         // Media3's UI classes are @UnstableApi; the opt-in lint check would
         // otherwise fail release builds.
@@ -49,3 +50,9 @@ dependencies {
     implementation("org.nanohttpd:nanohttpd-websocket:2.3.1")
     implementation("com.google.zxing:core:3.5.3")
 }
+
+// Full JDK for javac via toolchain (host may only have a JRE); resolved by
+// the foojay convention plugin in settings.
+kotlin {
+    jvmToolchain(17)
+}