💥 feat!: add tag filtering for projects (#431)

- Card (project) images no longer require manual top/bottom margin
adjustments for proper spacing. Action needed: Review existing card
images as previous manual margin adjustments may now be
unnecessary/excessive.
- Sites using `cards.html` with tags will now load JavaScript by
default when tags are present. To maintain no-JS behaviour, explicitly
set `enable_cards_tag_filtering = false` in either `config.toml` or the
`_index.md` file where `cards.html` is used.

sass/parts/_posts_list.scss

@@ -11,6 +11,19 @@ $padding: 2.5rem;
     align-items: flex-start;
     background-color: var(--navbar-color);
     padding-block: $padding;
+    min-width: 13.5rem;
+
+    .thumbnail-image {
+        margin: 0;
+        margin-inline: auto;  // Centred by default.
+        max-width: 70%;
+    }
+
+    li.date + li.post-thumbnail .thumbnail-image {
+        // Styles for the thumbnail when there's a date above (either date or updated).
+        margin-inline: 0;  // Since metadata is left aligned, the image looks weird when centred.
+        margin-block-start: 0.7rem;
+    }
 
     ul {
         margin-inline-end: 0.7rem;
@@ -24,10 +37,6 @@ $padding: 2.5rem;
             white-space: nowrap;
         }
 
-        li.date {
-            width: 13.5rem;
-        }
-
         li.draft-label {
             width: fit-content;
             line-height: 1.2rem;
@@ -137,6 +146,10 @@ $padding: 2.5rem;
                 margin-inline-end: 0.3rem;
             }
         }
+
+        .post-thumbnail {
+            display: none;
+        }
     }
 
     .bloglist-content {