feat(posts): add rebuild_content_html server function

New admin-only server function that re-renders content_html and
toc_html for posts from their content_md:
- rebuild_all=false: only processes posts where content_html IS NULL
- rebuild_all=true: processes all non-deleted posts
- Processes rows one at a time to avoid table locks
- Invalidates post list and stats caches after rebuild

src/api/posts/mod.rs

@@ -10,6 +10,7 @@ mod list;
 mod search;
 mod tags;
 mod stats;
+mod rebuild;
 
 pub use types::*;
 pub use create::create_post;
@@ -20,6 +21,7 @@ pub use list::{list_published_posts, list_posts, get_posts_by_tag};
 pub use search::search_posts;
 pub use tags::list_tags;
 pub use stats::get_post_stats;
+pub use rebuild::rebuild_content_html;
 
 #[cfg(feature = "server")]
 pub use crate::api::markdown::render_markdown_enhanced;

src/api/posts/rebuild.rs

@@ -0,0 +1,61 @@
+use dioxus::prelude::*;
+
+#[cfg(feature = "server")]
+use super::helpers::get_current_admin_user;
+#[cfg(feature = "server")]
+use crate::api::error::AppError;
+use crate::db::pool::get_conn;
+
+#[server(RebuildContentHtml, "/api")]
+pub async fn rebuild_content_html(rebuild_all: bool) -> Result<u64, ServerFnError> {
+    let _user = get_current_admin_user().await?;
+
+    #[cfg(feature = "server")]
+    {
+        let client = get_conn().await.map_err(AppError::db_conn)?;
+
+        let query = if rebuild_all {
+            "SELECT id, content_md FROM posts WHERE deleted_at IS NULL ORDER BY id"
+        } else {
+            "SELECT id, content_md FROM posts WHERE deleted_at IS NULL AND content_html IS NULL ORDER BY id"
+        };
+
+        let rows = client.query(query, &[]).await.map_err(AppError::query)?;
+
+        let mut count: u64 = 0;
+
+        for row in &rows {
+            let id: i32 = row.get(0);
+            let content_md: String = row.get(1);
+
+            let rendered = crate::api::markdown::render_markdown_enhanced(&content_md);
+            let toc_html = if rendered.toc_html.is_empty() {
+                None::<String>
+            } else {
+                Some(rendered.toc_html)
+            };
+
+            client
+                .execute(
+                    "UPDATE posts SET content_html = $1, toc_html = $2, updated_at = NOW() WHERE id = $3",
+                    &[&rendered.html, &toc_html, &id],
+                )
+                .await
+                .map_err(AppError::tx)?;
+
+            count += 1;
+        }
+
+        if count > 0 {
+            crate::cache::invalidate_post_lists();
+            crate::cache::invalidate_post_stats();
+        }
+
+        Ok(count)
+    }
+
+    #[cfg(not(feature = "server"))]
+    {
+        Ok(0)
+    }
+}