feat(wallet): add P2PKH, P2SH-P2WPKH, and P2TR (Taproot/BIP86) address types

- ScriptKind.Taproot (BIP86, purpose 86', P2WPKH → witness v1 bech32m plm1p)
  derivation wired in DerivationPaths and ChainProfiles (xprv/xpub headers,
  no SLIP-132 standard for P2TR); NBitcoin ScriptPubKeyType.TaprootBIP86
- Wizard step StepScriptType inserted between passphrase and password: 4 radio
  buttons (Legacy / Wrapped SegWit / Native SegWit★ / Taproot), localized in
  6 languages; CreateOrRestore now uses SelectedScriptKind instead of hardcoded
  NativeSegwit; back navigation updated accordingly
- BIP86 golden-vector tests (Bip86TaprootTests): output key verified against
  official Bitcoin BIP86 addresses, plm1p prefix asserted

src/Core/Crypto/DerivationPaths.cs

@@ -22,12 +22,16 @@ public static class DerivationPaths
     /// <summary>Purpose BIP48 (multisig — fase successiva, §16 passo 8).</summary>
     public const int PurposeMultisig = 48;
 
+    /// <summary>Purpose BIP86 (P2TR key-path, Taproot).</summary>
+    public const int PurposeTaproot = 86;
+
     public static int PurposeFor(ScriptKind kind) => kind switch
     {
         ScriptKind.Legacy => PurposeLegacy,
         ScriptKind.WrappedSegwit => PurposeWrappedSegwit,
         ScriptKind.NativeSegwit => PurposeNativeSegwit,
         ScriptKind.WrappedSegwitMultisig or ScriptKind.NativeSegwitMultisig => PurposeMultisig,
+        ScriptKind.Taproot => PurposeTaproot,
         _ => throw new ArgumentOutOfRangeException(nameof(kind)),
     };
 
@@ -41,6 +45,7 @@ public static class DerivationPaths
         ScriptKind.Legacy => ScriptPubKeyType.Legacy,
         ScriptKind.WrappedSegwit => ScriptPubKeyType.SegwitP2SH,
         ScriptKind.NativeSegwit => ScriptPubKeyType.Segwit,
+        ScriptKind.Taproot => ScriptPubKeyType.TaprootBIP86,
         ScriptKind.WrappedSegwitMultisig or ScriptKind.NativeSegwitMultisig =>
             throw new NotSupportedException(
                 "I tipi multisig derivano da redeem script: supporto previsto con i wallet M-di-N (§4.5)."),