Add app source and tests

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

lib/Peach/utils/CommonUtils.dart

@@ -0,0 +1,69 @@
+/// Shared formatting helpers. Anything a screen would otherwise write inline
+/// to render a value belongs here, so the same quantity reads the same way
+/// everywhere in the app.
+library;
+
+/// Human-friendly "time ago" formatting.
+String timeAgo(DateTime t) {
+  final d = DateTime.now().difference(t);
+  if (d.inSeconds < 45) return 'just now';
+  if (d.inMinutes < 60) return '${d.inMinutes}m ago';
+  if (d.inHours < 24) return '${d.inHours}h ago';
+  if (d.inDays < 7) return '${d.inDays}d ago';
+  String two(int n) => n.toString().padLeft(2, '0');
+  return '${t.year}-${two(t.month)}-${two(t.day)}';
+}
+
+/// Byte count as B / KB / MB / GB.
+String formatBytes(int bytes) {
+  if (bytes < 1024) return '$bytes B';
+  if (bytes < 1024 * 1024) return '${(bytes / 1024).toStringAsFixed(1)} KB';
+  if (bytes < 1024 * 1024 * 1024) {
+    return '${(bytes / (1024 * 1024)).toStringAsFixed(1)} MB';
+  }
+  return '${(bytes / (1024 * 1024 * 1024)).toStringAsFixed(2)} GB';
+}
+
+/// An integer with thousands separators — offsets and message counts are
+/// unreadable without them.
+String formatCount(int value) {
+  final digits = value.abs().toString();
+  final out = StringBuffer(value < 0 ? '-' : '');
+  for (var i = 0; i < digits.length; i++) {
+    if (i > 0 && (digits.length - i) % 3 == 0) out.write(',');
+    out.write(digits[i]);
+  }
+  return out.toString();
+}
+
+/// `HH:MM` for a timestamp.
+String formatClock(DateTime t) {
+  String two(int n) => n.toString().padLeft(2, '0');
+  return '${two(t.hour)}:${two(t.minute)}';
+}
+
+/// The last segment of a path, accepting either separator and ignoring a
+/// trailing slash.
+String baseName(String path) {
+  final normalised = path.replaceAll('\\', '/').replaceAll(RegExp(r'/+$'), '');
+  final i = normalised.lastIndexOf('/');
+  return i >= 0 ? normalised.substring(i + 1) : normalised;
+}
+
+/// Joins a POSIX directory and a child name without doubling the separator.
+String joinRemote(String base, String name) {
+  final trimmed = base.endsWith('/')
+      ? base.substring(0, base.length - 1)
+      : base;
+  return '$trimmed/$name';
+}
+
+/// The parent of a POSIX path, bottoming out at `/`.
+String parentRemote(String path) {
+  final trimmed = path.endsWith('/') && path.length > 1
+      ? path.substring(0, path.length - 1)
+      : path;
+  final i = trimmed.lastIndexOf('/');
+  if (i <= 0) return '/';
+  return trimmed.substring(0, i);
+}