feat(about): Bento Grid layout + 7 content updates

Layout redesign:
- Add BentoGrid, BentoTile, DecoOrb components
- Add accent palette (purple/teal/mint/coral) to global tokens
- Rewrite about.astro using Bento Grid (12-col, surface variants)
- Decorative parallax blur orbs in 4 sections
- Value/process tiles use numerals 01-04 instead of emoji

Content updates per user feedback:
- Remove "Soloprenuer" emphasis
- Remove TOC ("เนื้อหาในหน้านี้") — not needed for short content
- Outsource + bot acknowledged as part of approach
- Replace AI stack with marketing intelligence tools
  (ad spy, SEO gap, trend tracking)
- No fabricated stat numbers — placeholders show "—"
  (only "5+ ปี" kept as verifiable, founded 2020)
- Post-delivery: small changes free, charge only for new features
- No Sprint methodology — flexible timeline, demo when ready

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

src/components/BentoGrid.astro

@@ -0,0 +1,39 @@
+---
+/**
+ * BentoGrid — 12-column asymmetric bento grid container.
+ * Use <BentoTile> as children.
+ *
+ * Example:
+ *   <BentoGrid>
+ *     <BentoTile span={6} surface="yellow">...</BentoTile>
+ *     <BentoTile span={4} surface="purple-soft">...</BentoTile>
+ *   </BentoGrid>
+ */
+---
+
+<div class="bento-grid stagger">
+  <slot />
+</div>
+
+<style>
+  .bento-grid {
+    display: grid;
+    grid-template-columns: repeat(12, 1fr);
+    grid-auto-rows: minmax(80px, auto);
+    gap: 16px;
+    position: relative;
+  }
+
+  @media (max-width: 1024px) {
+    .bento-grid {
+      grid-template-columns: repeat(6, 1fr);
+    }
+  }
+
+  @media (max-width: 640px) {
+    .bento-grid {
+      grid-template-columns: 1fr;
+      gap: 12px;
+    }
+  }
+</style>