Add sort_by ordering for the log viewer, with a missing-param fallback/drop toggle (ticket 045)

/api/logs now accepts sort_by (an already-declared param name) and
sort_missing_fallback: lines carrying that param are ordered by its value,
while lines missing it are either appended in ottyl_seq order (fallback,
the default) or dropped from the response. Default ottyl_ts-tracking
order is unchanged when sort_by is omitted.

The log viewer (both the inline panel and its popout) exposes this as a
"Sort by" control next to the column picker, persisted to localStorage
under one shared key (ottyl.logPreview.sort) — the same global-viewer-
setting convention already used for visible param columns and the log
viewer's height, since there's no per-dashboard scope for this to divide
by.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

src/dto.rs

@@ -78,8 +78,16 @@ pub struct LogsParams {
     pub start_ms: Option<i64>,
     pub end_ms: Option<i64>,
     pub limit: Option<usize>,
-    /// Raw FilterBar query string, e.g. `regex("error") and sequence<5`.
+    /// Raw FilterBar query string, e.g. `regex("error") and ottyl_seq<5`.
     pub filter: Option<String>,
+    /// Ticket 045: an already-declared param name to order the returned entries by, in place of the
+    /// default ingest order (which tracks `ottyl_ts`). `None` (the default) leaves ordering
+    /// unchanged.
+    pub sort_by: Option<String>,
+    /// Ticket 045: only meaningful alongside `sort_by`. `true` (the default) orders lines missing
+    /// that param among themselves by `ottyl_seq` and appends them after the sorted lines; `false`
+    /// drops those lines from the response entirely.
+    pub sort_missing_fallback: Option<bool>,
 }
 
 #[derive(Debug, Deserialize)]