Run CI orchestration and setup as Java 25 source programs

ci/Commands.java

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+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.*;
+import java.time.*;
+import java.util.*;
+import java.util.concurrent.*;
+
+/** Executes argument lists directly, without shell interpolation or credential logging. */
+class Commands {
+    record Result(int code, String output) {
+        String checked() {
+            if (code != 0) throw new Failure(code, "Command failed with exit status " + code);
+            return output.strip();
+        }
+    }
+    static class Failure extends RuntimeException {
+        final int exitCode;
+        Failure(int exitCode, String message) { super(message); this.exitCode = exitCode; }
+    }
+    Instant deadline;
+    volatile Process active;
+    Path log;
+    void renew(Duration timeout) { deadline = Instant.now().plus(timeout); }
+    void cancel() { Process process = active; if (process != null) stop(process); }
+    Commands(Duration timeout) { deadline = Instant.now().plus(timeout); }
+
+    Result execute(List<String> args, Path cwd, Map<String, String> env, String input, boolean echo) throws Exception {
+        if (!Instant.now().isBefore(deadline)) throw new Failure(124, "CI time limit exceeded");
+        ProcessBuilder builder = new ProcessBuilder(args).directory(cwd.toFile()).redirectErrorStream(true);
+        builder.environment().clear();
+        builder.environment().putAll(env);
+        Process process = builder.start();
+        active = process;
+        ByteArrayOutputStream captured = new ByteArrayOutputStream();
+        Path destination = log;
+        try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
+            Future<?> reader = executor.submit(() -> {
+                try (InputStream stream = process.getInputStream();
+                     OutputStream file = destination == null ? OutputStream.nullOutputStream()
+                             : Files.newOutputStream(destination, StandardOpenOption.CREATE, StandardOpenOption.APPEND)) {
+                    byte[] buffer = new byte[8192];
+                    int count;
+                    while ((count = stream.read(buffer)) != -1) {
+                        captured.write(buffer, 0, count);
+                        if (echo) { System.out.write(buffer, 0, count); System.out.flush(); }
+                        file.write(buffer, 0, count);
+                    }
+                } catch (IOException e) { throw new UncheckedIOException(e); }
+            });
+            try {
+                try (OutputStream stdin = process.getOutputStream()) {
+                    if (input != null) stdin.write(input.getBytes(StandardCharsets.UTF_8));
+                }
+                if (!process.waitFor(Math.max(1, Duration.between(Instant.now(), deadline).toMillis()), TimeUnit.MILLISECONDS)) {
+                    stop(process);
+                    throw new Failure(124, "CI time limit exceeded");
+                }
+                reader.get(10, TimeUnit.SECONDS);
+                return new Result(process.exitValue(), captured.toString(StandardCharsets.UTF_8));
+            } finally {
+                if (process.isAlive()) stop(process);
+                active = null;
+            }
+        }
+    }
+
+    private static void stop(Process process) {
+        process.descendants().forEach(ProcessHandle::destroyForcibly);
+        process.destroyForcibly();
+    }
+}