refactor: per-wallet delete with monochrome styling

- Replace 'Danger Zone' section with per-wallet [delete] links in wallet list
- Each wallet shows a [delete] text link (dashed underline, monochrome)
- Clicking opens confirmation modal for that specific wallet
- Remove all red-500 styling, use standard monochrome border-border/text-fg
- Confirmation modal uses bg-well border-dashed border-border
- No longer assumes 'selected wallet' — operates on specific wallet index
- Password verification retained for delete confirmation

src/popup/index.html

@@ -842,26 +842,9 @@
                     <div id="settings-denied-sites"></div>
                 </div>
 
-                <div class="border-t border-border-light pt-3 mt-3">
-                    <h3 class="font-bold mb-2">Delete wallet</h3>
-                    <label class="block text-xs text-muted mb-1"
-                        >Select wallet to delete:</label
-                    >
-                    <select
-                        id="delete-wallet-select"
-                        class="border border-border p-1 w-full text-sm bg-bg text-fg mb-2"
-                    ></select>
-                    <button
-                        id="btn-delete-wallet"
-                        class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
-                    >
-                        Delete...
-                    </button>
-                </div>
-
                 <div
                     id="delete-wallet-confirm"
-                    class="hidden border border-border border-dashed p-3 mt-2 mb-3"
+                    class="hidden bg-well p-3 mx-1 mb-3 border border-dashed border-border"
                 >
                     <h3 class="font-bold mb-1">Confirm Deletion</h3>
                     <p class="text-xs text-muted mb-2">