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/create_variants.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python3
+"""Create responsive image variants and patch existing HTML img tags."""
+
+from __future__ import annotations
+
+import argparse
+import os
+import re
+import sys
+from pathlib import Path
+
+from generate import log, write_text_atomic
+from images import create_responsive_variants, iter_source_images
+
+HERO_IMG_RE = re.compile(
+    r'<img src="/img/(\d{4}-\d{2}-\d{2})\.jpg" alt="([^"]*)" width="560" height="420">'
+)
+THUMB_IMG_RE = re.compile(
+    r'<img src="/img/(\d{4}-\d{2}-\d{2})\.jpg" alt="([^"]*)" width="360" height="203" loading="lazy">'
+)
+
+
+def patch_html_images(path: Path, descriptors: dict[str, dict[str, str]]) -> bool:
+    html = path.read_text(encoding="utf-8")
+    original = html
+
+    def replace_hero(match: re.Match[str]) -> str:
+        date_iso, alt = match.group(1), match.group(2)
+        image = descriptors.get(date_iso)
+        if not image:
+            return match.group(0)
+        return (
+            f'<img src="{image["src"]}" srcset="{image["srcset"]}" sizes="{image["sizes"]}" '
+            f'alt="{alt}" width="560" height="420">'
+        )
+
+    def replace_thumb(match: re.Match[str]) -> str:
+        date_iso, alt = match.group(1), match.group(2)
+        image = descriptors.get(date_iso)
+        if not image:
+            return match.group(0)
+        return (
+            f'<img src="{image["thumb_src"]}" srcset="{image["thumb_srcset"]}" '
+            f'sizes="{image["thumb_sizes"]}" alt="{alt}" width="360" height="203" loading="lazy">'
+        )
+
+    html = HERO_IMG_RE.sub(replace_hero, html)
+    html = THUMB_IMG_RE.sub(replace_thumb, html)
+    if html != original:
+        write_text_atomic(path, html)
+        log(f"patched images in {path}")
+        return True
+    return False
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description="Create responsive hero image variants")
+    parser.add_argument("--site-dir", default=None)
+    args = parser.parse_args()
+
+    repo_root = Path(__file__).resolve().parent.parent
+    site_dir = Path(args.site_dir or os.environ.get("SITE_DIR", repo_root / "public"))
+    img_dir = site_dir / "img"
+
+    descriptors: dict[str, dict[str, str]] = {}
+    for source in iter_source_images(img_dir):
+        date_iso = source.stem
+        descriptor = create_responsive_variants(img_dir, date_iso)
+        if descriptor:
+            descriptors[date_iso] = descriptor
+            log(f"created variants for {date_iso}")
+
+    patched = 0
+    targets = [site_dir / "index.html", site_dir / "archiv" / "index.html"]
+    targets.extend(sorted((site_dir / "archiv").glob("2026-*.html")))
+    for path in targets:
+        if path.exists():
+            patched += patch_html_images(path, descriptors)
+
+    log(f"done, {len(descriptors)} image set(s), patched {patched} html file(s)")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())