diff --git a/.jules/bolt.md b/.jules/bolt.md
index b08b203a..16f06974 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -4,3 +4,6 @@
 ## 2026-07-12 - Optimize renderTaskRow DOM allocations
 **Learning:** Caching unattached template nodes and instantiating them via `.cloneNode(false)` reduces DOM instantiation overhead in O(N) render loops significantly.
 **Action:** Apply this optimization to other hot-path rendering elements such as rows, cells, and stack containers.
+## 2026-07-24 - Performance penalty of String.padStart in hot loops
+**Learning:** Using `String(val).padStart(2, '0')` in hot rendering paths (like generating date string formatters) incurs significant JS-to-C++ allocation overhead compared to simple ternary logic (e.g., `val < 10 ? '0' : ''`). A benchmark revealed that `padStart` is an order of magnitude slower.
+**Action:** Replace `padStart(2, '0')` with inline ternary string concatenation in all frequently called formatting functions to reduce overhead.
diff --git a/app.js b/app.js
index b8c62279..cf1371f6 100644
--- a/app.js
+++ b/app.js
@@ -2664,22 +2664,28 @@ function clamp(value, min, max) {
   return Math.min(max, Math.max(min, value));
 }
 
+// ⚡ Bolt: Replace String.padStart with inline ternary for faster hot-path date formatting
 function formatDateInput(date) {
   const year = date.getUTCFullYear();
-  const month = String(date.getUTCMonth() + 1).padStart(2, '0');
-  const day = String(date.getUTCDate()).padStart(2, '0');
-  return `${year}-${month}-${day}`;
+  const m = date.getUTCMonth() + 1;
+  const d = date.getUTCDate();
+  return `${year}-${m < 10 ? '0' : ''}${m}-${d < 10 ? '0' : ''}${d}`;
 }
 
+// ⚡ Bolt: Replace String.padStart with inline ternary for faster hot-path date formatting
 function formatLocalDateInput(date) {
   const year = date.getFullYear();
-  const month = String(date.getMonth() + 1).padStart(2, '0');
-  const day = String(date.getDate()).padStart(2, '0');
-  return `${year}-${month}-${day}`;
+  const m = date.getMonth() + 1;
+  const d = date.getDate();
+  return `${year}-${m < 10 ? '0' : ''}${m}-${d < 10 ? '0' : ''}${d}`;
 }
 
+// ⚡ Bolt: Replace String.padStart with inline ternary for faster hot-path date formatting
 function formatCompactDate(date) {
-  return `${date.getFullYear()}${String(date.getMonth() + 1).padStart(2, '0')}${String(date.getDate()).padStart(2, '0')}`;
+  const year = date.getFullYear();
+  const m = date.getMonth() + 1;
+  const d = date.getDate();
+  return `${year}${m < 10 ? '0' : ''}${m}${d < 10 ? '0' : ''}${d}`;
 }
 
 function formatPercent(value, digits) {