widgets: add PNG output format support

Widget image generation produces PNG internally — the pipeline opens
OH_Partner_frame.png, composites text and kudos onto it, and returns the
result via MiniMagick's to_blob, which emits PNG bytes. Previously those
bytes were served as image/gif regardless of what was requested, which
is a lie about the Content-Type.

Add proper ?format=png support by renaming render_image_for_gif_format
to render_image_for_image_format (and the "not supported" equivalent)
across all five widget controllers. PNG requests now receive
Content-Type: image/png with the same underlying bytes — no conversion
needed since the data is already PNG. GIF requests preserve existing
behavior for backward compatibility.

Author: mattst88

app/controllers/account_widgets_controller.rb

@@ -2,7 +2,7 @@
 
 class AccountWidgetsController < WidgetsController
   before_action :set_account
-  before_action :render_image_for_gif_format
+  before_action :render_image_for_image_format
   before_action :account_context, only: :index
 
   def index

app/controllers/organization_widgets_controller.rb

@@ -2,7 +2,7 @@
 
 class OrganizationWidgetsController < WidgetsController
   before_action :set_organization
-  before_action :render_not_supported_for_gif_format
+  before_action :render_not_supported_for_image_format
   before_action :render_iframe_for_js_format
   before_action :organization_context, only: :index
 

app/controllers/project_widgets_controller.rb

@@ -3,8 +3,8 @@
 class ProjectWidgetsController < WidgetsController
   helper :Projects, :Analyses
   before_action :set_project
-  before_action :render_image_for_gif_format, only: %i[partner_badge thin_badge]
-  before_action :render_not_supported_for_gif_format, except: %i[partner_badge thin_badge index]
+  before_action :render_image_for_image_format, only: %i[partner_badge thin_badge]
+  before_action :render_not_supported_for_image_format, except: %i[partner_badge thin_badge index]
   before_action :render_iframe_for_js_format
   before_action :project_context, only: :index
 

app/controllers/stack_widgets_controller.rb

@@ -3,7 +3,7 @@
 class StackWidgetsController < WidgetsController
   before_action :set_widget
   before_action :set_stack_and_account
-  before_action :render_not_supported_for_gif_format
+  before_action :render_not_supported_for_image_format
   before_action :render_iframe_for_js_format
   before_action :account_context, only: :index
 

app/controllers/widgets_controller.rb

@@ -22,19 +22,25 @@ def set_widget
                     .new(permitted_params)
   end
 
-  def render_image_for_gif_format
-    return unless request.format.gif?
+  def render_image_for_image_format
+    return unless request.format.gif? || request.format.png?
 
     cache_key = "#{@widget.parent.class.name}/#{@widget.parent.id}/#{@widget.name}"
     image = Rails.cache.fetch(cache_key, expires_in: 4.hours) { @widget.image }
-    send_data(image, disposition: 'inline', type: 'image/gif', filename: 'widget.gif', status: 200)
+    if request.format.png?
+      send_data(image, disposition: 'inline', type: 'image/png', filename: 'widget.png', status: 200)
+    else
+      send_data(image, disposition: 'inline', type: 'image/gif', filename: 'widget.gif', status: 200)
+    end
   end
 
-  def render_not_supported_for_gif_format
-    return unless request.format.gif?
+  def render_not_supported_for_image_format
+    return unless request.format.gif? || request.format.png?
 
     image = Rails.cache.fetch('not_supported_widget') { WidgetBadge::Thin.create([text: 'Not supported']) }
-    send_data(image, disposition: 'inline', type: 'image/gif', filename: 'widget.gif', status: 406)
+    mime_type = request.format.png? ? 'image/png' : 'image/gif'
+    filename = request.format.png? ? 'widget.png' : 'widget.gif'
+    send_data(image, disposition: 'inline', type: mime_type, filename: filename, status: 406)
   end
 
   def render_iframe_for_js_format