Set up AI dev environment for recordingtest (#2)

- CLAUDE.md with collaboration rules and Planner/Generator/Evaluator cycle
- .claude/ agents, commands, skills, hooks per Claude Code conventions
- Sprint Contracts for sut-prober, normalizer, recorder, player, diff-reporter
- SUT catalog (EG-BIM Modeler, 187 plugins) and .gitignore excluding SUT tree
- PROGRESS.md / PLAN.md as shared agent handoff state
- Solution scaffold targeting sut-prober PoC

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Recordingtest.SutProber/PluginScanner.cs

@@ -0,0 +1,32 @@
+namespace Recordingtest.SutProber;
+
+public sealed record PluginEntry(string Name, string Path, IReadOnlyList<string> Dlls, long SizeBytes);
+
+public static class PluginScanner
+{
+    public static List<PluginEntry> Scan(string sutRoot)
+    {
+        var pluginRoot = System.IO.Path.Combine(sutRoot, "Plugins");
+        if (!Directory.Exists(pluginRoot)) return new();
+
+        var entries = new List<PluginEntry>();
+        foreach (var dir in Directory.EnumerateDirectories(pluginRoot).OrderBy(d => d, StringComparer.Ordinal))
+        {
+            var dlls = Directory.EnumerateFiles(dir, "*.dll", SearchOption.TopDirectoryOnly)
+                .Select(System.IO.Path.GetFileName)
+                .Where(n => n is not null)
+                .Select(n => n!)
+                .OrderBy(n => n, StringComparer.Ordinal)
+                .ToList();
+
+            long size = 0;
+            foreach (var f in Directory.EnumerateFiles(dir, "*", SearchOption.AllDirectories))
+                size += new FileInfo(f).Length;
+
+            var name = System.IO.Path.GetFileName(dir);
+            var relPath = System.IO.Path.GetRelativePath(".", dir).Replace('\\', '/');
+            entries.Add(new PluginEntry(name, relPath, dlls, size));
+        }
+        return entries;
+    }
+}