feat(ui): add bug report button in Help overlay and GitHub issue template

Adds a "Report a bug" button in Help → Info that opens the GitHub
new-issue page directly in the system browser (via TopLevel.Launcher,
cross-platform on desktop and Android).

Adds .github/ISSUE_TEMPLATE/bug_report.yml — a structured issue form
that collects version, platform, network, repro steps, expected vs
actual behavior, and logs before submission.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,91 @@
+name: Bug Report
+description: Report a problem with Palladium Wallet
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to report a bug.
+        Please fill in every section — incomplete reports are hard to reproduce and may be closed.
+
+  - type: input
+    id: version
+    attributes:
+      label: Wallet version
+      description: Shown in Help → Info (e.g. `1.0.0`).
+      placeholder: "1.0.0"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: platform
+    attributes:
+      label: Platform
+      options:
+        - Windows
+        - Linux
+        - Android
+    validations:
+      required: true
+
+  - type: dropdown
+    id: network
+    attributes:
+      label: Network
+      options:
+        - Mainnet
+        - Testnet
+        - Regtest
+    validations:
+      required: true
+
+  - type: textarea
+    id: description
+    attributes:
+      label: What happened?
+      description: Describe the bug clearly and concisely. What did you see? What did you expect?
+      placeholder: "When I click … the wallet shows … instead of …"
+    validations:
+      required: true
+
+  - type: textarea
+    id: steps
+    attributes:
+      label: Steps to reproduce
+      description: Numbered steps that reliably trigger the bug.
+      placeholder: |
+        1. Open the wallet
+        2. Go to …
+        3. Click …
+        4. Observe …
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected behavior
+      description: What should have happened instead?
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs / error messages
+      description: |
+        Paste any error dialogs, crash messages, or relevant log output.
+        Leave blank if none.
+      render: text
+    validations:
+      required: false
+
+  - type: checkboxes
+    id: checklist
+    attributes:
+      label: Before submitting
+      options:
+        - label: I searched existing issues and this is not a duplicate
+          required: true
+        - label: I reproduced this on the latest available version
+          required: false

src/App/Localization/Loc.cs

@@ -62,6 +62,7 @@ public sealed class Loc
             "SPV-Wallet für die Kryptowährung Palladium (PLM)."],
         ["help.tab.info"]         = ["Info",                                                               "Info",                         "Info",                                 "Info",                                     "Info",                                     "Info"],
         ["help.tab.donate"]       = ["Dona",                                                               "Donate",                       "Donar",                                "Faire un don",                             "Doar",                                     "Spenden"],
+        ["help.bug.report"]       = ["Segnala un bug",                                                     "Report a bug",                 "Informar un error",                    "Signaler un bug",                          "Reportar um bug",                          "Fehler melden"],
         ["donate.desc"]           = [
             "Se questo wallet ti è utile, considera una piccola donazione allo sviluppatore.",
             "If you find this wallet useful, consider a small donation to the developer.",

src/App/Views/MainView.axaml

@@ -1555,6 +1555,9 @@
                                                    Foreground="{DynamicResource TextSecondaryBrush}"/>
                                     </StackPanel>
                                     <TextBlock Text="{Binding Loc[help.info]}" TextWrapping="Wrap"/>
+                                    <Button Content="{Binding Loc[help.bug.report]}"
+                                            Click="OnOpenBugReportClick"
+                                            HorizontalAlignment="Left"/>
                                     <Border BorderBrush="{DynamicResource BorderSubtleBrush}"
                                             BorderThickness="0,1,0,0" Margin="0,4,0,0"/>
                                     <StackPanel Spacing="4">

src/App/Views/MainView.axaml.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using Avalonia;
 using Avalonia.Controls;
@@ -128,6 +129,14 @@ public partial class MainView : UserControl
             vm.IsHelpOpen = false;
     }
 
+    private async void OnOpenBugReportClick(object? sender, RoutedEventArgs e)
+    {
+        var launcher = TopLevel.GetTopLevel(this)?.Launcher;
+        if (launcher is not null)
+            await launcher.LaunchUriAsync(new Uri(
+                "https://github.com/davide3011/PalladiumWallet/issues/new?assignees=&labels=bug&template=bug_report.yml"));
+    }
+
     // Esc (desktop) or Back (Android) closes the topmost open overlay.
     protected override void OnKeyDown(KeyEventArgs e)
     {