Replace image pipeline with profile-driven variants

- add image normalization profiles and thumbnail profiles
- generate source, full-size variant, and thumbnail image artifacts
- rewrite canonical image URLs through the first configured profile
- emit explicit image Media RSS groups with named thumbnails
- preserve legacy image paths when image conversion is disabled
- cover cache-hit source paths, inline image handling, and thumbnail export

repub/utils.py

@@ -43,6 +43,50 @@ def local_audio_path(s: str) -> str:
     return local_file_path(s)
 
 
+def image_guid(source_url: str) -> str:
+    return hashlib.sha1(to_bytes(source_url)).hexdigest()  # nosec
+
+
+def image_extension(mimetype_or_extension: str | None, source_url: str = "") -> str:
+    if mimetype_or_extension:
+        if mimetype_or_extension.startswith("."):
+            extension = mimetype_or_extension
+        elif "/" in mimetype_or_extension:
+            extension = mimetypes.guess_extension(mimetype_or_extension) or ""
+        else:
+            extension = f".{mimetype_or_extension.lstrip('.')}"
+        if extension == ".jpe":
+            return ".jpg"
+        return extension
+    guessed = Path(source_url).suffix
+    if guessed == ".jpe":
+        return ".jpg"
+    if guessed:
+        return guessed
+    return ".img"
+
+
+def source_image_path(source_url: str, mimetype_or_extension: str | None = None) -> str:
+    extension = image_extension(mimetype_or_extension, source_url)
+    return f"source/{image_guid(source_url)}{extension}"
+
+
+def published_image_path(source_url: str, profile: Mapping[str, Any]) -> str:
+    return variant_media_path(f"full/{image_guid(source_url)}", profile, hashed=True)
+
+
+def canonical_published_image_path(
+    source_url: str, profiles: Sequence[Mapping[str, Any]]
+) -> str:
+    if not profiles:
+        raise ValueError("Missing image normalization profiles")
+    return published_image_path(source_url, profiles[0])
+
+
+def thumbnail_image_path(source_url: str, profile: Mapping[str, Any]) -> str:
+    return variant_media_path(f"thumbs/{image_guid(source_url)}", profile, hashed=True)
+
+
 def profile_settings_hash(profile: Mapping[str, Any]) -> str:
     settings = {
         key: value
@@ -65,6 +109,8 @@ def variant_media_path(
 def published_media_path(
     file_type: FileType, source_url: str, profile: Mapping[str, Any]
 ) -> str:
+    if file_type == FileType.IMAGE:
+        return published_image_path(source_url, profile)
     if file_type == FileType.AUDIO:
         return variant_media_path(local_audio_path(source_url), profile, hashed=True)
     if file_type == FileType.VIDEO:
@@ -79,6 +125,8 @@ def canonical_published_media_path(
         raise ValueError(f"Missing transcode profiles for {file_type.value}")
     # The first configured profile is the public URL contract. Reordering profiles
     # changes published URLs for already-mirrored media.
+    if file_type == FileType.IMAGE:
+        return canonical_published_image_path(source_url, profiles)
     return published_media_path(file_type, source_url, profiles[0])