More step spans where flame graphs showed time with nothing under it (#350)

A week of traces folded with query.py flame left whole requests opaque:
entries_in at 46-82 ms a request with the page's query and its enclosures
together, /api/art 37 ms, /api/status 95 ms, PATCH /api/feeds/{id} 72 ms and
DELETE 45 ms. Each now has a step around what it waits on: the page and its
enclosures; the artwork cache, the check that a feed names it, the fetch and the
write; the status counts; and in changing or leaving a feed, each database call,
the wait for the catalogue's lock and storing it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ipx/src/db.rs

@@ -1468,8 +1468,7 @@ impl Db {
              LEFT JOIN entry_state s ON s.user_id = {user} AND s.feed_id = e.feed_id AND s.guid = e.guid
              ORDER BY {order}"
         );
-        let mut rows = self
-            .rows(&sql, a.0)
+        let mut rows = tracing::Instrument::instrument(self.rows(&sql, a.0), step("page"))
             .await?
             .iter()
             .map(|r| {
@@ -1499,11 +1498,14 @@ impl Db {
 
         // Only the guids on this page, so a feed with thousands of entries stays cheap. A page
         // can span feeds, so each file is matched to its row by feed as well as guid, below.
-        let encs = enclosures::Entity::find()
-            .filter(enclosures::Column::Guid.is_in(rows.iter().map(|r| r.guid.clone())))
-            .order_by_asc(enclosures::Column::Id)
-            .all(&self.orm)
-            .await?;
+        let encs = tracing::Instrument::instrument(
+            enclosures::Entity::find()
+                .filter(enclosures::Column::Guid.is_in(rows.iter().map(|r| r.guid.clone())))
+                .order_by_asc(enclosures::Column::Id)
+                .all(&self.orm),
+            step("enclosures"),
+        )
+        .await?;
         for enc in encs {
             if let Some(row) = rows.iter_mut().find(|r| r.guid == enc.guid && r.feed_id == enc.feed_id) {
                 row.enclosures.push(EncRow::from(enc));