chore(github): complete issue/PR templates and wire in-app bug report to them

Add a feature request template and a config.yml (blank issues disabled,
security reports routed to SECURITY.md) alongside the existing bug report
template, plus a PR template with a checklist matching the project's
security rules. Point the app's "Report a bug" button at the new GitHub
template now that the repo is hosted there instead of the old self-hosted
tracker.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -28,17 +28,6 @@ body:
     validations:
       required: true
 
-  - type: dropdown
-    id: network
-    attributes:
-      label: Network
-      options:
-        - Mainnet
-        - Testnet
-        - Regtest
-    validations:
-      required: true
-
   - type: textarea
     id: description
     attributes:

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Security vulnerability
+    url: https://github.com/davide3011/PalladiumWallet/security/policy
+    about: Please report security vulnerabilities privately, not as a public issue. See SECURITY.md.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,55 @@
+name: Feature Request
+description: Suggest an idea or improvement for Palladium Wallet
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to suggest an improvement.
+
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem
+      description: What problem are you trying to solve? Is it related to something you find missing or frustrating?
+      placeholder: "I'm always frustrated when …"
+    validations:
+      required: true
+
+  - type: textarea
+    id: solution
+    attributes:
+      label: Proposed solution
+      description: Describe what you'd like to happen.
+    validations:
+      required: true
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives considered
+      description: Any alternative solutions or workarounds you've considered.
+    validations:
+      required: false
+
+  - type: dropdown
+    id: platform
+    attributes:
+      label: Affected platform(s)
+      multiple: true
+      options:
+        - Windows
+        - Linux
+        - Android
+        - CLI
+        - All
+    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