fix: remove trailing slash from site.url to prevent double-slash URLs

site.url had a trailing slash (added for Mastodon rel=me verification),
which caused double slashes in all URL constructions like
{{ site.url }}/auth → https://rmendes.net//auth

This broke IndieAuth login — indielogin.com read the authorization_endpoint
link tag with //auth and redirected users there, which 404'd in nginx.

Split into site.url (no slash, for URL construction) and site.me /
site.author.url (with slash, for Mastodon rel=me strict matching).

Also fixed twitter:image meta tags to use smart slash logic matching
the og:image pattern (check if path starts with / before prepending one).

_data/site.js

@@ -62,14 +62,16 @@ function buildSocialFromFeeds() {
   return links;
 }
 
-// Ensure URL has trailing slash (Mastodon rel="me" verification uses strict string match)
+// site.url: no trailing slash — used as URL base for path concatenation ({{ site.url }}/path)
-const siteUrl = (process.env.SITE_URL || "https://example.com").replace(/\/$/, "") + "/";
+// site.me / site.author.url: trailing slash — Mastodon rel="me" requires exact match
+const siteUrlBase = (process.env.SITE_URL || "https://example.com").replace(/\/$/, "");
+const siteUrlWithSlash = siteUrlBase + "/";
 
 export default {
   // Basic site info
   name: process.env.SITE_NAME || "My IndieWeb Blog",
-  url: siteUrl,
+  url: siteUrlBase,
-  me: siteUrl,
+  me: siteUrlWithSlash,
   locale: process.env.SITE_LOCALE || "en",
   description:
     process.env.SITE_DESCRIPTION ||
@@ -78,7 +80,7 @@ export default {
   // Author info (shown in h-card, about page, etc.)
   author: {
     name: process.env.AUTHOR_NAME || "Blog Author",
-    url: siteUrl,
+    url: siteUrlWithSlash,
     avatar: process.env.AUTHOR_AVATAR || "/images/default-avatar.svg",
     title: process.env.AUTHOR_TITLE || "",
     bio: process.env.AUTHOR_BIO || "Welcome to my IndieWeb blog.",

_includes/layouts/base.njk

@@ -45,11 +45,11 @@
   <meta name="twitter:title" content="{{ ogTitle }}">
   <meta name="twitter:description" content="{{ ogDesc }}">
   {% if ogPhoto and ogPhoto != "" and (ogPhoto | length) > 10 %}
-  <meta name="twitter:image" content="{% if 'http' in ogPhoto %}{{ ogPhoto }}{% else %}{{ site.url }}/{{ ogPhoto }}{% endif %}">
+  <meta name="twitter:image" content="{% if 'http' in ogPhoto %}{{ ogPhoto }}{% else %}{{ site.url }}{% if ogPhoto[0] != '/' %}/{% endif %}{{ ogPhoto }}{% endif %}">
   {% elif image and image != "" and (image | length) > 10 %}
-  <meta name="twitter:image" content="{% if 'http' in image %}{{ image }}{% else %}{{ site.url }}/{{ image }}{% endif %}">
+  <meta name="twitter:image" content="{% if 'http' in image %}{{ image }}{% else %}{{ site.url }}{% if image[0] != '/' %}/{% endif %}{{ image }}{% endif %}">
   {% elif contentImage and contentImage != "" and (contentImage | length) > 10 %}
-  <meta name="twitter:image" content="{% if 'http' in contentImage %}{{ contentImage }}{% else %}{{ site.url }}/{{ contentImage }}{% endif %}">
+  <meta name="twitter:image" content="{% if 'http' in contentImage %}{{ contentImage }}{% else %}{{ site.url }}{% if contentImage[0] != '/' %}/{% endif %}{{ contentImage }}{% endif %}">
   {% elif hasOgImage %}
   <meta name="twitter:image" content="{{ site.url }}/og/{{ ogSlug }}.png">
   {% endif %}