seo: per-locale HowTo schema (8 new keys × 6 languages)

HowTo schema was hardcoded English — now uses {{HOWTO_*}}
placeholders. All 3 rich-result schemas are now locale-aware:
  - FAQPage  (expandable SERP snippets)
  - HowTo    (step-by-step SERP snippets)
  - SoftwareApplication (entity understanding)

SoftwareApplication and Organization use language-neutral
brand name — no locale keys needed.

website/template.html

@@ -96,28 +96,28 @@
     {
       "@context": "https://schema.org",
       "@type": "HowTo",
-      "name": "How to synchronize videos with friends using KoalaSync",
-      "description": "Watch any video in perfect sync with friends across YouTube, Netflix, Twitch and more. No sign-up, no tracking.",
+      "name": "{{HOWTO_TITLE}}",
+      "description": "{{HOWTO_DESC}}",
       "step": [
         {
           "@type": "HowToStep",
           "position": 1,
-          "name": "Install the browser extension",
-          "text": "Add KoalaSync to your browser from Chrome Web Store or Firefox Add-ons. It works on any website with a video element.",
+          "name": "{{HOWTO_STEP_1_NAME}}",
+          "text": "{{HOWTO_STEP_1_TEXT}}",
           "url": "https://sync.koalastuff.net/#how-it-works"
         },
         {
           "@type": "HowToStep",
           "position": 2,
-          "name": "Create a room",
-          "text": "Open the extension popup and click Create New Room. The invite link is automatically copied to your clipboard.",
+          "name": "{{HOWTO_STEP_2_NAME}}",
+          "text": "{{HOWTO_STEP_2_TEXT}}",
           "url": "https://sync.koalastuff.net/#how-it-works"
         },
         {
           "@type": "HowToStep",
           "position": 3,
-          "name": "Share and sync",
-          "text": "Send the invite link to your friends. Pick a video tab and enjoy synchronized playback in real time.",
+          "name": "{{HOWTO_STEP_3_NAME}}",
+          "text": "{{HOWTO_STEP_3_TEXT}}",
           "url": "https://sync.koalastuff.net/#how-it-works"
         }
       ]