Pre-launch design sync with Figma spec (#2154)

* Add lookbook + viewcomponent, organize design system file

* Build menu component

* Button updates

* More button fixes

* Replace all menus with new ViewComponent

* Checkpoint: fix tests, all buttons and menus converted

* Split into Link and Button components for clarity

* Button cleanup

* Simplify custom confirmation configuration in views

* Finalize button, link component API

* Add toggle field to custom form builder + Component

* Basic tabs component

* Custom tabs, convert all menu / tab instances in app

* Gem updates

* Centralized icon helper

* Update all icon usage to central helper

* Lint fixes

* Centralize all disclosure instances

* Dialog replacements

* Consolidation of all dialog styles

* Test fixes

* Fix app layout issues, move to component with slots

* Layout simplification

* Flakey test fix

* Fix dashboard mobile issues

* Finalize homepage

* Lint fixes

* Fix shadows and borders in dark mode

* Fix tests

* Remove stale class

* Fix filled icon logic

* Move transparent? to public interface

app/views/assistant_messages/_assistant_message.html.erb

@@ -5,7 +5,7 @@
     <details class="group mb-1">
       <summary class="flex items-center gap-2">
         <p class="text-secondary text-sm">Assistant reasoning</p>
-        <%= lucide_icon "chevron-down", class: "group-open:transform group-open:rotate-180 text-secondary w-5" %>
+        <%= icon("chevron-down", class: "group-open:transform group-open:rotate-180") %>
       </summary>
 
       <div class="prose prose--ai-chat"><%= markdown(assistant_message.content) %></div>

app/views/assistant_messages/_tool_calls.html.erb

@@ -2,7 +2,7 @@
 
 <details class="my-2 group mb-4">
   <summary class="text-secondary text-xs cursor-pointer flex items-center gap-2">
-    <%= lucide_icon "chevron-right", class: "group-open:transform group-open:rotate-90 text-secondary w-5" %>
+    <%= icon("chevron-right", class: "group-open:transform group-open:rotate-90") %>
     <p>Tool Calls</p>
   </summary>