GingerCal 1.4: bundled TLS 1.2, no bridge needed

CalDAV now goes through Minamp's own HTTP/TLS client (Bouncy Castle TLS 1.2, Mozilla
roots, keep-alive) instead of Apache HttpClient on Android 2.3's TLS 1.0, as the iPod
version does with BearSSL. The phone reaches the normal https:// Nextcloud address at
home and away; a pinned self-signed server or the old bridge still works.

- NetHttp transport; requests run on big-stack threads (the handshake overflows
  AsyncTask/IntentService stacks on Android 2.x)
- http:// -> https:// redirects on the same host are followed; other hosts still refused
- bridge wording replaced in Galician and English; README updated
- NetTest (TLS + CalDAV discovery through the new transport) replaces BridgeTest

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/org/gingercal/net/Threads.java

@@ -0,0 +1,43 @@
+package org.gingercal.net;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+
+/**
+ * Background threads with big stacks. Android 2.x gives new threads ~16 KB of stack, and the
+ * bundled TLS handshake + certificate parsing needs far more; overflowing it kills the app.
+ * 256 KB is the most Dalvik allows.
+ */
+public final class Threads {
+    public static final long STACK = 256 * 1024;
+
+    private Threads() {}
+
+    public static Thread create(Runnable r, String name) {
+        Thread t = new Thread(null, r, name, STACK);
+        t.setDaemon(true);
+        return t;
+    }
+
+    public static void start(Runnable r, String name) {
+        create(r, name).start();
+    }
+
+    public static ExecutorService pool(final String name, int n) {
+        ThreadFactory f = new ThreadFactory() {
+            private int count;
+            public synchronized Thread newThread(Runnable r) { return create(r, name + "-" + (++count)); }
+        };
+        return n == 1 ? Executors.newSingleThreadExecutor(f) : Executors.newFixedThreadPool(n, f);
+    }
+
+    /** Readable one-liner for any failure, including Errors such as StackOverflowError. */
+    public static String describe(Throwable t) {
+        String m = t.getMessage();
+        String cls = t.getClass().getSimpleName();
+        if (m == null || m.length() == 0) return cls;
+        if (t instanceof java.io.IOException) return m;
+        return cls + ": " + m;
+    }
+}