flatten modules to repo root, vendor deps, repair Eclipse build paths

Move api, engine, ui-console and ui-desktop out of modules/ up to the
repo root and drop the empty exception project (GuessMarketException now
lives in api).

Vendor gson, jaxb, okhttp, openjfx and tomcat under lib/, and group the
JUnit standalone jar into lib/junit/ alongside them.

Rewrite every .classpath: drop the copy-pasted optional="true" that was
masking real build path errors, point the library entries at ../lib/,
and put the JUnit jar on the test source folders so the placeholder
AppTest classes compile.

ui-desktop: take the JavaFX jars off the modulepath (there is no
module-info.java, so module="true" left the packages unresolvable) and
add a Launcher that calls Application.launch, avoiding the "JavaFX
runtime components are missing" check without VM arguments.

engine: add LocalGuessMarketService and the GuessMarketContext provider
interface, and give GuessMarketException the no-arg and cause
constructors they need.

2 files changed, 31 insertions, 0 deletions

diff --git a/ui-desktop/src/main/java/market/guess/ui/desktop/App.java b/ui-desktop/src/main/java/market/guess/ui/desktop/App.java
new file mode 100644
index 0000000..f0b2b7a
--- /dev/null
+++ b/ui-desktop/src/main/java/market/guess/ui/desktop/App.java
@@ -0,0 +1,22 @@
+package market.guess.ui.desktop;
+
+import javafx.application.Application;
+import javafx.scene.Scene;
+import javafx.scene.control.Label;
+import javafx.scene.layout.StackPane;
+import javafx.stage.Stage;
+
+public class App extends Application {
+  @Override
+  public void start(Stage stage) throws Exception {
+    var javaVersion = System.getProperty("java.version");
+    var openjfxVersion = System.getProperty("javafx.version");
+
+    var label =
+        new Label("Hello. JavaFX " + openjfxVersion + ", running on Java " + javaVersion + ".");
+    var scene = new Scene(new StackPane(label), 640, 480);
+
+    stage.setScene(scene);
+    stage.show();
+  }
+}
diff --git a/ui-desktop/src/main/java/market/guess/ui/desktop/Launcher.java b/ui-desktop/src/main/java/market/guess/ui/desktop/Launcher.java
new file mode 100644
index 0000000..ffe9505
--- /dev/null
+++ b/ui-desktop/src/main/java/market/guess/ui/desktop/Launcher.java
@@ -0,0 +1,9 @@
+package market.guess.ui.desktop;
+
+import javafx.application.Application;
+
+public final class Launcher {
+  public static void main(String[] args) {
+    Application.launch(App.class, args);
+  }
+}