Add wizard UI, general-assembly resolution, and test suite

Restructure Form1 into a sequential wizard (database -> import -> raw ->
recursive component resolution -> completeness/STEP report), fix
case-sensitivity bugs in codice/tipo_file lookups and a word-boundary gap
in the assembly scanner that missed _D100-style sub-assembly references,
and treat the distinta's general assembly as an ordinary CSV row (derived
from the DBP_<codice>_<timestamp> filename) instead of special-casing it
throughout. Also adds CadSearchGui.Tests (xUnit) covering the scanner,
filename parsing, and the case-insensitive DB lookup behavior.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CadSearchGui/Indexer.cs

@@ -18,12 +18,10 @@ public sealed record ScanProgress(
 
 public static class Indexer
 {
-    public static readonly string[] CartelleRadice = { "__Accessori", "__B.end", "__Corpi", "__Fondi", "Unificati", "Commerciali" };
-
     private static readonly Regex FilenameRegex =
         new(@"^(?<codice>.+)\.(?<tipo>[A-Za-z0-9]+)\.(?<versione>\d+)$", RegexOptions.Compiled);
 
-    private const string Schema = """
+    internal const string Schema = """
         CREATE TABLE IF NOT EXISTS files (
             id INTEGER PRIMARY KEY,
             percorso_completo TEXT UNIQUE NOT NULL,
@@ -67,8 +65,12 @@ public static class Indexer
             schemaCmd.ExecuteNonQuery();
         }
 
+        // Indicizza tutte le cartelle di primo livello sotto la radice (non un elenco fisso),
+        // così una nuova cartella creata sulla share entra nell'indice senza modificare il codice.
+        var cartelleRadice = Directory.GetDirectories(root).Select(p => Path.GetFileName(p)!).ToArray();
+
         var previsti = new Dictionary<string, long>();
-        foreach (var cartella in CartelleRadice)
+        foreach (var cartella in cartelleRadice)
         {
             using var cmd = connection.CreateCommand();
             cmd.CommandText = "SELECT COUNT(*) FROM files WHERE cartella_radice = @c";
@@ -80,7 +82,7 @@ public static class Indexer
         var sw = Stopwatch.StartNew();
         long fattiTotali = 0;
 
-        foreach (var cartella in CartelleRadice)
+        foreach (var cartella in cartelleRadice)
         {
             ct.ThrowIfCancellationRequested();
 
@@ -233,7 +235,7 @@ public static class Indexer
         cmd.Parameters["@modifica"].Value = modifica;
     }
 
-    private static (string codice, string tipo, int? versione) ParseFilename(string nomeFile)
+    internal static (string codice, string tipo, int? versione) ParseFilename(string nomeFile)
     {
         var match = FilenameRegex.Match(nomeFile);
         if (match.Success)