Add post tags, with a tag page and two side-column modules

Posts can now carry tags, set on the post form as a checklist of the
blog's existing tags plus a comma-separated box for new ones (no JS).
A tag is a name and a unique slug, so "Go" and "go" are one tag and
Greek tags get readable URLs; tags no post uses any more are deleted.

On the blog, tags appear under the post date and link to /tag/<slug>,
which lists the published posts from every page, paginated like a page.
Two new layout modules show them: a Tags list (with counts, by use) and
a Tag cloud (alphabetical, sized by use). Both are only fetched when a
visible module needs them.

The article loop and pager move to a shared postlist partial; while
there, the pager stops adding a trailing slash — /news/?p=2 was a 404
because a {page} wildcard never matches one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sd8UPWrvyYCLj97JexNw3A

1 files changed, 4 insertions, 2 deletions

diff --git a/internal/store/pages.go b/internal/store/pages.go
index 55cad33..3d5b02d 100644
--- a/internal/store/pages.go
+++ b/internal/store/pages.go
@@ -105,8 +105,10 @@ func (bs *BlogStore) UpdatePage(ctx context.Context, p *Page) error {
 }
 
 func (bs *BlogStore) DeletePage(ctx context.Context, id int64) error {
-	_, err := bs.db.Exec(ctx, `DELETE FROM pages WHERE id=$1 AND NOT is_home`, id)
-	return err
+	if _, err := bs.db.Exec(ctx, `DELETE FROM pages WHERE id=$1 AND NOT is_home`, id); err != nil {
+		return err
+	}
+	return deleteOrphanTags(ctx, bs.db) // its posts went with it
 }
 
 // SetHomePage moves the home flag to the given page.