feat: add Wave 3 homepage sections (11 Vue components) [3/3] (#10142)

## Summary
Adds all 11 homepage section components for the comfy.org marketing
site.

## Changes (incremental from #10141)
- HeroSection.vue: C monogram left, headline right, CTAs
- SocialProofBar.vue: 12 enterprise logos + metrics
- ProductShowcase.vue: PLACEHOLDER workflow demo
- ValuePillars.vue: Build/Customize/Refine/Automate/Run
- UseCaseSection.vue: PLACEHOLDER industries
- CaseStudySpotlight.vue: PLACEHOLDER bento grid
- TestimonialsSection.vue: Filterable by industry
- GetStartedSection.vue: 3-step flow
- CTASection.vue: Desktop/Cloud/API cards
- ManifestoSection.vue: Method Not Magic
- AcademySection.vue: Learning paths CTA
- Updated index.astro + zh-CN/index.astro

## Stack (via Graphite)
- #10140 [1/3] Scaffold
- #10141 [2/3] Layout Shell
- **[3/3] Homepage Sections** ← this PR (top of stack)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10142-feat-add-Wave-3-homepage-sections-11-Vue-components-3-3-3266d73d36508194aa8ee9385733ddb9)
by [Unito](https://www.unito.io)

apps/website/src/components/CaseStudySpotlight.vue

@@ -0,0 +1,77 @@
+<!-- TODO: Replace placeholder content with real quotes and case studies -->
+<script setup lang="ts">
+const studies = [
+  {
+    title: 'New Pipelines with Chord Mode',
+    body: 'For AI-assisted texture and environment generation across studio pipelines.',
+    highlight: false,
+    gridClass: 'md:row-span-2'
+  },
+  {
+    title: 'AI-Assisted Texture and Environment',
+    body: 'For AI-assisted texture and environment generation across studio pipelines.',
+    highlight: false,
+    gridClass: 'min-h-[300px] lg:col-span-2'
+  },
+  {
+    title: 'Open-sourced the Chord Mode',
+    body: 'For AI-assisted texture and environment generation across studio pipelines.',
+    highlight: false,
+    gridClass: 'min-h-[200px]'
+  },
+  {
+    title: 'Environment Generation',
+    body: 'For AI-assisted texture and environment generation across studio pipelines.',
+    highlight: true,
+    gridClass: 'min-h-[200px]'
+  }
+]
+</script>
+
+<template>
+  <section class="bg-black px-6 py-24">
+    <div class="mx-auto max-w-7xl">
+      <header class="mb-12">
+        <h2 class="text-3xl font-bold text-white">Customer Stories</h2>
+        <p class="mt-2 text-smoke-700">
+          See how leading studios use Comfy in production
+        </p>
+      </header>
+
+      <!-- Bento grid -->
+      <div
+        class="relative grid grid-cols-1 gap-4 md:grid-cols-2 lg:grid-cols-3"
+      >
+        <article
+          v-for="study in studies"
+          :key="study.title"
+          class="flex flex-col justify-end rounded-2xl border border-brand-yellow/30 p-6"
+          :class="[
+            study.gridClass,
+            study.highlight ? 'bg-brand-yellow' : 'bg-charcoal-600'
+          ]"
+        >
+          <h3
+            class="font-semibold"
+            :class="study.highlight ? 'text-black' : 'text-white'"
+          >
+            {{ study.title }}
+          </h3>
+          <p
+            class="mt-2 text-sm"
+            :class="study.highlight ? 'text-black/70' : 'text-smoke-700'"
+          >
+            {{ study.body }}
+          </p>
+          <a
+            href="/case-studies"
+            class="mt-4 text-sm underline"
+            :class="study.highlight ? 'text-black' : 'text-brand-yellow'"
+          >
+            READ CASE STUDY
+          </a>
+        </article>
+      </div>
+    </div>
+  </section>
+</template>