Give the studio windows an IntelliJ style dark theme with FlatLaf

FlatLaf is loaded at runtime through slimjar like the other libraries.
Every studio window now opens with FlatLaf's dark look tuned to the
IntelliJ New UI colours, and shares a small kit of controls: a flat
toolbar, toolbar buttons and tabs, search boxes, a status bar and the
rounded cards drawn over maps.

Model used: Claude Opus 5.5

gradle/libs.versions.toml

@@ -36,6 +36,7 @@ caffeine = "3.2.1" # https://central.sonatype.com/artifact/com.github.ben-manes.
 byte-buddy = "1.17.6" # https://central.sonatype.com/artifact/net.bytebuddy/byte-buddy
 dom4j = "2.2.0" # https://central.sonatype.com/artifact/org.dom4j/dom4j
 jaxen = "2.0.0" # https://central.sonatype.com/artifact/jaxen/jaxen
+flatlaf = "3.7.2" # https://central.sonatype.com/artifact/com.formdev/flatlaf
 
 # Script Engine
 kotlin = "2.2.0"
@@ -84,6 +85,7 @@ byteBuddy-core = { module = "net.bytebuddy:byte-buddy", version.ref = "byte-budd
 byteBuddy-agent = { module = "net.bytebuddy:byte-buddy-agent", version.ref = "byte-buddy" }
 dom4j = { module = "org.dom4j:dom4j", version.ref = "dom4j" }
 jaxen = { module = "jaxen:jaxen", version.ref = "jaxen" }
+flatlaf = { module = "com.formdev:flatlaf", version.ref = "flatlaf" }
 
 # Script Engine
 kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib-jdk8", version.ref = "kotlin" }