Fix OAuth mobile app support with custom URL schemes

- Configure Doorkeeper to allow custom URL schemes (maybeapp://)
- Disable force_ssl_in_redirect_uri to support non-HTTPS schemes
- Add custom Doorkeeper views with mobile OAuth detection
- Disable Turbo for mobile OAuth flows to prevent redirect interference
- Add display parameter preservation through OAuth flow
- Create custom Doorkeeper layouts with proper styling
- Add comprehensive integration tests for mobile OAuth flows
- Ensure all OAuth pages use proper doorkeeper/application layout

This allows the mobile app to complete OAuth authorization flows
without the web app interfering with custom URL scheme redirects.

🤖 Generated with Claude Code

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

app/views/doorkeeper/authorizations/error.html.erb

@@ -0,0 +1,22 @@
+<div class="bg-container rounded-xl p-6 space-y-6">
+  <div class="text-center space-y-2">
+    <div class="mx-auto w-12 h-12 rounded-full bg-destructive-surface flex items-center justify-center mb-4">
+      <%= icon("alert-circle", class: "w-6 h-6 text-destructive") %>
+    </div>
+    <h1 class="text-2xl font-medium text-primary"><%= t('doorkeeper.authorizations.error.title') %></h1>
+  </div>
+
+  <div class="bg-surface-inset rounded-lg p-4">
+    <p class="text-sm text-secondary">
+      <%= (local_assigns[:error_response] ? error_response : @pre_auth.error_response).body[:error_description] %>
+    </p>
+  </div>
+
+  <div class="text-center">
+    <%= render LinkComponent.new(
+      text: "Go back",
+      href: "javascript:history.back()",
+      variant: :secondary
+    ) %>
+  </div>
+</div>

app/views/doorkeeper/authorizations/form_post.html.erb

@@ -0,0 +1,22 @@
+<div class="bg-container rounded-xl p-6 space-y-6">
+  <div class="text-center space-y-2">
+    <div class="mx-auto w-12 h-12 rounded-full bg-surface-inset flex items-center justify-center mb-4">
+      <%= icon("loader-circle", class: "w-6 h-6 text-primary animate-spin") %>
+    </div>
+    <h1 class="text-2xl font-medium text-primary"><%= t('.title') %></h1>
+    <p class="text-sm text-secondary">Redirecting you back to the application...</p>
+  </div>
+</div>
+
+<% turbo_disabled = @pre_auth.redirect_uri&.start_with?('maybeapp://') || params[:display] == 'mobile' %>
+<%= form_tag @pre_auth.redirect_uri, method: :post, name: :redirect_form, authenticity_token: false, data: { turbo: !turbo_disabled } do %>
+  <% auth.body.compact.each do |key, value| %>
+    <%= hidden_field_tag key, value %>
+  <% end %>
+<% end %>
+
+<script>
+  window.onload = function () {
+    document.forms['redirect_form'].submit();
+  };
+</script>

app/views/doorkeeper/authorizations/new.html.erb

@@ -0,0 +1,76 @@
+<% if params[:redirect_uri]&.start_with?('maybeapp://') || params[:display] == 'mobile' %>
+  <meta name="turbo-visit-control" content="reload">
+<% end %>
+
+<div class="bg-container rounded-xl p-6 space-y-6">
+  <div class="space-y-2 text-center">
+    <p class="text-sm text-secondary">
+      <%= raw t('.prompt', client_name: content_tag(:span, @pre_auth.client.name, class: 'font-medium text-primary')) %>
+    </p>
+  </div>
+
+  <% if @pre_auth.scopes.count > 0 %>
+    <div class="bg-surface-inset rounded-lg p-4 space-y-3">
+      <p class="text-sm font-medium text-primary"><%= t('.able_to') %>:</p>
+      <ul class="space-y-2">
+        <% @pre_auth.scopes.each do |scope| %>
+          <li class="flex items-start gap-2 text-sm text-secondary">
+            <%= icon("check", class: "w-4 h-4 mt-0.5 text-success") %>
+            <span><%= t scope, scope: [:doorkeeper, :scopes] %></span>
+          </li>
+        <% end %>
+      </ul>
+    </div>
+  <% end %>
+
+  <div class="space-y-3">
+    <% turbo_disabled = params[:redirect_uri]&.start_with?('maybeapp://') || params[:display] == 'mobile' %>
+    <%= form_tag oauth_authorization_path, method: :post, class: "w-full", data: { turbo: !turbo_disabled } do %>
+      <%= hidden_field_tag :client_id, @pre_auth.client.uid, id: nil %>
+      <%= hidden_field_tag :redirect_uri, @pre_auth.redirect_uri, id: nil %>
+      <%= hidden_field_tag :state, @pre_auth.state, id: nil %>
+      <%= hidden_field_tag :response_type, @pre_auth.response_type, id: nil %>
+      <%= hidden_field_tag :response_mode, @pre_auth.response_mode, id: nil %>
+      <%= hidden_field_tag :scope, @pre_auth.scope, id: nil %>
+      <%= hidden_field_tag :code_challenge, @pre_auth.code_challenge, id: nil %>
+      <%= hidden_field_tag :code_challenge_method, @pre_auth.code_challenge_method, id: nil %>
+      <% if params[:display].present? %>
+        <%= hidden_field_tag :display, params[:display], id: nil %>
+      <% end %>
+      <%= render ButtonComponent.new(
+        text: t('doorkeeper.authorizations.buttons.authorize'),
+        variant: :primary,
+        size: :lg,
+        full_width: true,
+        href: oauth_authorization_path,
+        data: { disable_with: "Authorizing..." }
+      ) %>
+    <% end %>
+    
+    <%= form_tag oauth_authorization_path, method: :delete, class: "w-full", data: { turbo: !turbo_disabled } do %>
+      <%= hidden_field_tag :client_id, @pre_auth.client.uid, id: nil %>
+      <%= hidden_field_tag :redirect_uri, @pre_auth.redirect_uri, id: nil %>
+      <%= hidden_field_tag :state, @pre_auth.state, id: nil %>
+      <%= hidden_field_tag :response_type, @pre_auth.response_type, id: nil %>
+      <%= hidden_field_tag :response_mode, @pre_auth.response_mode, id: nil %>
+      <%= hidden_field_tag :scope, @pre_auth.scope, id: nil %>
+      <%= hidden_field_tag :code_challenge, @pre_auth.code_challenge, id: nil %>
+      <%= hidden_field_tag :code_challenge_method, @pre_auth.code_challenge_method, id: nil %>
+      <% if params[:display].present? %>
+        <%= hidden_field_tag :display, params[:display], id: nil %>
+      <% end %>
+      <%= render ButtonComponent.new(
+        text: t('doorkeeper.authorizations.buttons.deny'),
+        variant: :outline,
+        size: :lg,
+        full_width: true,
+        href: oauth_authorization_path,
+        data: { disable_with: "Denying..." }
+      ) %>
+    <% end %>
+  </div>
+
+  <p class="text-xs text-tertiary text-center">
+    By authorizing, you allow this app to access your Maybe data according to the permissions above.
+  </p>
+</div>

app/views/doorkeeper/authorizations/show.html.erb

@@ -0,0 +1,17 @@
+<div class="bg-container rounded-xl p-6 space-y-6">
+  <div class="text-center space-y-2">
+    <div class="mx-auto w-12 h-12 rounded-full bg-success-surface flex items-center justify-center mb-4">
+      <%= icon("check", class: "w-6 h-6 text-success") %>
+    </div>
+    <h1 class="text-2xl font-medium text-primary"><%= t('.title') %></h1>
+  </div>
+
+  <div class="bg-surface-inset rounded-lg p-4">
+    <p class="text-xs text-secondary mb-2">Authorization Code:</p>
+    <code id="authorization_code" class="block text-sm font-mono text-primary break-all"><%= params[:code] %></code>
+  </div>
+
+  <p class="text-sm text-secondary text-center">
+    Copy this code and paste it into the application.
+  </p>
+</div>