Add article dates, brand OG image, launch SEO checklist

- Add datePublished/dateModified to Article JSON-LD on the 11 dated
  articles (curated once from EN, applied to all languages)
- Replace og-default.jpg with the official brand OG image (1200x630)
- Add docs/launch-seo-checklist.md (go-live steps: redirects, Search
  Console, analytics, rich-result validation, monitoring)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/seo_inject.py

@@ -39,6 +39,22 @@ SECTION_NAMES = {
 }
 HOME_CRUMB = {"en": "Home", "mk": "Дома", "si": "Domov"}
 
+# Article dates (ISO), curated once from the English pages (dates are
+# language-independent). Emitted as datePublished/dateModified in Article schema.
+ARTICLE_DATES = {
+    "blog/how-to-open-slovenian-bank-account": {"modified": "2026-08-01"},
+    "news/proof-of-means-updated-2026": {"published": "2026-08-01"},
+    "projects/humanitarian-tournament-in-maribor": {"published": "2025-04-05"},
+    "projects/in-memory-of-frosina-kulakova": {"published": "2025-02-08"},
+    "projects/in-memory-of-the-kochani-victims": {"published": "2025-03-21"},
+    "projects/macedonian-student-night-in-ljubljana": {"published": "2022-10-08"},
+    "projects/meet-student-slovenia-2023": {"published": "2023-09-18"},
+    "projects/meet-student-slovenia-2024": {"published": "2024-09-16"},
+    "projects/morning-coffee-in-front-of-ctk": {"published": "2024-06-08"},
+    "projects/paint-and-wine-at-sunset": {"published": "2025-03-08"},
+    "projects/watching-handball-together-in-slovenia": {"published": "2025-01-25"},
+}
+
 START, END = "<!-- SEO:START -->", "<!-- SEO:END -->"
 BLOCK_RE = re.compile(re.escape(START) + r".*?" + re.escape(END) + r"\s*", re.DOTALL)
 TITLE_RE = re.compile(r"(<title>.*?</title>)", re.DOTALL)
@@ -187,6 +203,12 @@ def article_schema(lang, path, content, canon, desc, ogimg):
     }
     if not article["description"]:
         del article["description"]
+    dates = ARTICLE_DATES.get(path)
+    if dates:
+        pub = dates.get("published") or dates.get("modified")
+        mod = dates.get("modified") or dates.get("published")
+        article["datePublished"] = pub
+        article["dateModified"] = mod
     crumbs = {
         "@context": "https://schema.org", "@type": "BreadcrumbList",
         "itemListElement": [