Add passkey prompt dismissal and consolidate company admin navigation

- Add "Don't ask me again" to passkey enrollment prompt (PasskeyPromptDismissed
  field on ApplicationUser; DismissPrompt POST action; migration applied)
- Add Subscription & Features button to Companies/Index btn-group and
  Companies/Edit header for direct navigation to SubscriptionManagement/Manage
- Add Edit Company back-link on SubscriptionManagement/Manage
- Remove duplicate AI Features section from Companies/Edit (managed exclusively
  via Subscription & Features page)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Views/Passkey/EnrollPrompt.cshtml

@@ -121,6 +121,13 @@
                     <a id="pk-skip-link" href="@returnUrl" class="btn btn-outline-secondary btn-lg">
                         Maybe later
                     </a>
+                    <form method="post" action="/Passkey/DismissPrompt">
+                        @Html.AntiForgeryToken()
+                        <input type="hidden" name="returnUrl" value="@returnUrl" />
+                        <button type="submit" class="btn btn-link text-muted w-100" style="font-size:0.85rem;">
+                            Don't ask me again
+                        </button>
+                    </form>
                 </div>
             </div>