feat: Snippets "The Lab" — category filters, search, language badges, code preview, modal keyboard nav (#72)

* fix: pass locale explicitly to Hero and force-dynamic on locale-sensitive API routes

- Hero.tsx: pass locale prop directly to getTranslations instead of
  relying on setRequestLocale async storage, which can be lost during
  Next.js RSC streaming
- book-reviews route: replace revalidate=300 with force-dynamic to
  prevent cached English responses being served to German locale requests
- content/page route: add runtime=nodejs and force-dynamic (was missing
  both, violating CLAUDE.md API route conventions)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix: scroll to top on locale switch and remove dashes from hero text

- HeaderClient: track locale prop changes with useRef and call
  window.scrollTo on switch to reliably reset scroll position
- messages/en.json + de.json: replace em dash with comma and remove
  hyphens from Self-Hoster/Full-Stack in hero description

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Initial plan

* feat: improve Snippets/The Lab UI with category filters, search, language badges and code preview

Agent-Logs-Url: https://github.com/denshooter/portfolio/sessions/4a562022-cad7-4b4f-8bc4-1be022ecbf1e

Co-authored-by: denshooter <44590296+denshooter@users.noreply.github.com>

---------

Co-authored-by: denshooter <dennis@konkol.net>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: denshooter <44590296+denshooter@users.noreply.github.com>

package-lock.json

@@ -26,7 +26,6 @@
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         "next": "^15.5.7",
         "next-intl": "^4.7.0",
-        "next-themes": "^0.4.6",
         "node-cache": "^5.1.2",
         "node-fetch": "^2.7.0",
         "nodemailer": "^7.0.11",
@@ -11348,16 +11347,6 @@
         }
       }
     },
-    "node_modules/next-themes": {
-      "version": "0.4.6",
-      "resolved": "https://registry.npmjs.org/next-themes/-/next-themes-0.4.6.tgz",
-      "integrity": "sha512-pZvgD5L0IEvX5/9GWyHMf3m8BKiVQwsCMHfoFosXtXBMnaS0ZnIJ9ST4b4NqLVKDEm8QBxoNNGNaBv2JNF6XNA==",
-      "license": "MIT",
-      "peerDependencies": {
-        "react": "^16.8 || ^17 || ^18 || ^19 || ^19.0.0-rc",
-        "react-dom": "^16.8 || ^17 || ^18 || ^19 || ^19.0.0-rc"
-      }
-    },
     "node_modules/next/node_modules/@swc/helpers": {
       "version": "0.5.15",
       "resolved": "https://registry.npmjs.org/@swc/helpers/-/helpers-0.5.15.tgz",