Restore renderIntervals() for pace field changes

Pace field uses 'change' event (fires on blur), so keyboard is already
closed when handler runs. Safe to use renderIntervals() to properly
update the speed field display.

Speed field still uses direct DOM update to keep keyboard open during typing.

https://claude.ai/code/session_01PX2BfeXuZgwAnfHckfS3Gw

Author: claude

src/inner_templates/workouteditor/workout-editor-app.js

@@ -919,13 +919,10 @@
                 const field = FIELD_DEFS.find(f => f.key === key);
                 if (field && field.syncWith) {
                     state.intervals[index][field.syncWith] = speed;
-                    // Update speed field directly without re-render to keep focus
-                    const speedInput = document.querySelector(`input[data-index="${index}"][data-key="${field.syncWith}"]`);
-                    if (speedInput) {
-                        speedInput.value = speed;
-                    }
                 }
             }
+            // Re-render to update speed field (pace uses 'change' event so keyboard is already closed)
+            renderIntervals();
             updateChart();
             updateStatus();
             return;