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/static/app.css

@@ -419,6 +419,9 @@
   .rotate-180 {
     rotate: 180deg;
   }
+  .transform {
+    transform: var(--tw-rotate-x,) var(--tw-rotate-y,) var(--tw-rotate-z,) var(--tw-skew-x,) var(--tw-skew-y,);
+  }
   .animate-pulse {
     animation: var(--animate-pulse);
   }
@@ -1221,6 +1224,26 @@
   inherits: false;
   initial-value: 0;
 }
+@property --tw-rotate-x {
+  syntax: "*";
+  inherits: false;
+}
+@property --tw-rotate-y {
+  syntax: "*";
+  inherits: false;
+}
+@property --tw-rotate-z {
+  syntax: "*";
+  inherits: false;
+}
+@property --tw-skew-x {
+  syntax: "*";
+  inherits: false;
+}
+@property --tw-skew-y {
+  syntax: "*";
+  inherits: false;
+}
 @property --tw-space-y-reverse {
   syntax: "*";
   inherits: false;
@@ -1460,6 +1483,11 @@
       --tw-translate-x: 0;
       --tw-translate-y: 0;
       --tw-translate-z: 0;
+      --tw-rotate-x: initial;
+      --tw-rotate-y: initial;
+      --tw-rotate-z: initial;
+      --tw-skew-x: initial;
+      --tw-skew-y: initial;
       --tw-space-y-reverse: 0;
       --tw-space-x-reverse: 0;
       --tw-divide-y-reverse: 0;