Left-align log-table headers to match their left-aligned data cells

Last Heard (and other log-style tables sharing this pattern) render
every <td> with align="left", but headers inherit the sitewide
table { text-align: center; } with nothing overriding it - so the
caption drifts toward the middle of wide columns (most visible on
Target) while the actual data underneath hugs the left edge. Looks
like a column-boundary misalignment at a glance, but it's a text-align
mismatch; measured actual cell boundaries and they line up exactly.

Scoped via a new .log-table class rather than changing table th
sitewide, since ~90% of the dashboard's other tables intentionally
keep centered cells (only 6-7 files use align="left" data cells).

css/pistar-css-mini.php

@@ -614,6 +614,11 @@ table th {
     border-bottom: 2px solid var(--accent);
 }
 
+/* See css/pistar-css.php for why this is scoped to .log-table only. */
+table.log-table th {
+    text-align: left;
+}
+
 table tr:nth-child(even) {
     background: var(--table-even);
 }