chore: Update theme colors and add new Inter variable fonts (#13347)

# Pull Request Template

## Description

This PR includes the following updates:

1. Updated the design system color tokens by introducing new tokens for
surfaces, overlays, buttons, labels, and cards, along with refinements
to existing shades.
2. Refreshed both light and dark themes with adjusted background,
border, and solid colors.
3. Replaced static Inter font files with the Inter variable font
(including italic), supporting weights from 100–900.
4. Added custom font weights (420, 440, 460, 520) along with custom
typography classes to enable more fine-grained and consistent typography
control.


## Type of change

- [x] New feature (non-breaking change which adds functionality)


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Pranav <pranav@chatwoot.com>

app/javascript/dashboard/components-next/HelpCenter/ArticleCard/ArticleCard.vue

@@ -126,7 +126,7 @@ const handleClick = id => {
   <CardLayout>
     <div class="flex justify-between w-full gap-1">
       <span
-        class="text-base cursor-pointer hover:underline underline-offset-2 hover:text-n-blue-text text-n-slate-12 line-clamp-1"
+        class="text-base cursor-pointer hover:underline underline-offset-2 hover:text-n-blue-11 text-n-slate-12 line-clamp-1"
         @click="handleClick(id)"
       >
         {{ title }}

app/javascript/dashboard/components-next/HelpCenter/CategoryCard/CategoryCard.vue

@@ -83,7 +83,7 @@ const handleAction = ({ action, value }) => {
       <div class="flex justify-between w-full gap-2">
         <div class="flex items-center justify-start w-full min-w-0 gap-2">
           <span
-            class="text-base truncate cursor-pointer hover:underline underline-offset-2 hover:text-n-blue-text text-n-slate-12"
+            class="text-base truncate cursor-pointer hover:underline underline-offset-2 hover:text-n-blue-11 text-n-slate-12"
             @click="handleClick(slug)"
           >
             {{ categoryTitleWithIcon }}

app/javascript/dashboard/components-next/HelpCenter/HelpCenterLayout.vue

@@ -58,7 +58,7 @@ const togglePortalSwitcher = () => {
 </script>
 
 <template>
-  <section class="flex flex-col w-full h-full overflow-hidden bg-n-background">
+  <section class="flex flex-col w-full h-full overflow-hidden bg-n-surface-1">
     <header class="sticky top-0 z-10 px-6 pb-3 lg:px-0">
       <div class="w-full max-w-[60rem] mx-auto lg:px-6">
         <div

app/javascript/dashboard/components-next/HelpCenter/LocaleCard/LocaleCard.vue

@@ -60,7 +60,7 @@ const handleAction = ({ action, value }) => {
         </span>
         <span
           v-if="isDefault"
-          class="bg-n-alpha-2 h-6 inline-flex items-center justify-center rounded-md text-xs border-px border-transparent text-n-blue-text px-2 py-0.5"
+          class="bg-n-alpha-2 h-6 inline-flex items-center justify-center rounded-md text-xs border-px border-transparent text-n-blue-11 px-2 py-0.5"
         >
           {{ $t('HELP_CENTER.LOCALES_PAGE.LOCALE_CARD.DEFAULT') }}
         </span>

app/javascript/dashboard/components-next/HelpCenter/Pages/CategoryPage/CategoryForm.vue

@@ -246,7 +246,7 @@ defineExpose({ state, isSubmitDisabled });
           variant="faded"
           color="slate"
           :label="t('HELP_CENTER.CATEGORY_PAGE.CATEGORY_DIALOG.BUTTONS.CANCEL')"
-          class="w-full bg-n-alpha-2 text-n-blue-text hover:bg-n-alpha-3"
+          class="w-full bg-n-alpha-2 text-n-blue-11 hover:bg-n-alpha-3"
           @click="handleCancel"
         />
         <Button