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/styles/global.css

@@ -15,6 +15,16 @@
   --color-primary: #fed400;        /* yellow accent */
   --color-primary-dark: #e6c100;   /* hover state */
   --color-primary-light: #fff5b3;  /* tint for subtle backgrounds */
+  --color-primary-soft: #fff4b3;   /* bento tile surface */
+
+  /* Accent palette — for bento tile variety */
+  --color-purple: #7c3aed;
+  --color-purple-soft: #ede9fe;
+  --color-teal: #0d9488;
+  --color-teal-soft: #ccfbf1;
+  --color-mint: #10b981;
+  --color-mint-soft: #d1fae5;
+  --color-coral: #f97316;
 
   --color-black: #0a0a0a;          /* primary text */
   --color-white: #ffffff;          /* pure white */