feat: Archiv-Backfill, responsive Bilder und Site-Meta

Ergänzt Backfill- und Hilfsskripte, erzeugt nach der Pixazo-Generierung
komprimierte srcset-Varianten, validiert leere Bilder und fügt Favicon,
Web Manifest sowie Open-Graph-/Twitter-Tags in die Templates ein.

Co-authored-by: Cursor <cursoragent@cursor.com>

generator/generate.py

@@ -15,6 +15,7 @@ import requests
 from jinja2 import Environment, FileSystemLoader
 
 import topics
+from images import create_responsive_variants, load_image_descriptor
 
 GERMAN_MONTHS = [
     "Januar",
@@ -205,7 +206,7 @@ def generate_hero_image(
     date_iso: str,
     prompt: str,
     negative_prompt: str,
-) -> str | None:
+) -> dict[str, str] | None:
     try:
         response = requests.post(
             "https://gateway.pixazo.ai/getImage/v1/getSDXLImage",
@@ -233,12 +234,18 @@ def generate_hero_image(
 
         img_response = requests.get(image_url, timeout=120)
         img_response.raise_for_status()
+        if len(img_response.content) < 50_000:
+            log(
+                f"warning: hero image for {date_iso} too small "
+                f"({len(img_response.content)} bytes), discarding"
+            )
+            return None
 
         img_dir = site_dir / "img"
         img_dir.mkdir(parents=True, exist_ok=True)
         img_path = img_dir / f"{date_iso}.jpg"
         img_path.write_bytes(img_response.content)
-        return f"/img/{date_iso}.jpg"
+        return create_responsive_variants(img_dir, date_iso)
     except (requests.RequestException, OSError, KeyError, TypeError, ValueError) as exc:
         log(f"warning: hero image generation failed: {exc}")
         return None
@@ -252,7 +259,8 @@ def render_template(name: str, context: dict) -> str:
     return env.get_template(name).render(**context)
 
 
-def build_archiv_entries(archive: list[dict]) -> list[dict]:
+def build_archiv_entries(archive: list[dict], site_dir: Path) -> list[dict]:
+    img_dir = site_dir / "img"
     entries = []
     for item in sorted(archive, key=lambda e: e["date"], reverse=True):
         prompts = item.get("prompts")
@@ -263,7 +271,9 @@ def build_archiv_entries(archive: list[dict]) -> list[dict]:
                 "backronym": item["backronym"],
                 "tagline": item["tagline"],
                 "url": f"/archiv/{item['date']}.html",
-                "image": f"/img/{item['date']}.jpg" if item.get("has_image") else None,
+                "image": load_image_descriptor(img_dir, item["date"])
+                if item.get("has_image")
+                else None,
                 "topics": item.get("topics", []),
                 "prompts": prompts if isinstance(prompts, dict) else None,
             }
@@ -323,18 +333,26 @@ def main() -> int:
         log("PIXAZO_API_KEY not set, skipping hero image")
 
     human_date = date_human(today)
-    startup_context = {
+    startup_base = {
         "date": date_iso,
         "date_human": human_date,
         "theme": theme,
         "hero_image": hero_image,
         "s": llm_json,
+        "site_url": os.environ.get("SITE_URL", "https://mobea.de"),
     }
-    startup_html = render_template("startup.html.j2", startup_context)
+    startup_html = render_template(
+        "startup.html.j2",
+        {**startup_base, "canonical_path": "/"},
+    )
+    archiv_day_html = render_template(
+        "startup.html.j2",
+        {**startup_base, "canonical_path": f"/archiv/{date_iso}.html"},
+    )
 
     archiv_day_path = site_dir / "archiv" / f"{date_iso}.html"
     write_text_atomic(index_path, startup_html)
-    write_text_atomic(archiv_day_path, startup_html)
+    write_text_atomic(archiv_day_path, archiv_day_html)
     log(f"wrote {index_path} and {archiv_day_path}")
 
     archive_entry = {
@@ -357,9 +375,21 @@ def main() -> int:
     save_json_atomic(data_dir / "archive.json", archive)
     log(f"updated {data_dir / 'archive.json'}")
 
+    latest_image = next(
+        (
+            f"/img/{entry['date']}.jpg"
+            for entry in sorted(archive, key=lambda e: e["date"], reverse=True)
+            if entry.get("has_image")
+        ),
+        "/og-default.jpg",
+    )
     archiv_html = render_template(
         "archiv.html.j2",
-        {"entries": build_archiv_entries(archive)},
+        {
+            "entries": build_archiv_entries(archive, site_dir),
+            "site_url": os.environ.get("SITE_URL", "https://mobea.de"),
+            "og_image": latest_image,
+        },
     )
     write_text_atomic(site_dir / "archiv" / "index.html", archiv_html)
     log(f"wrote {site_dir / 'archiv' / 'index.html'}")