Stamp "now" events to the second, not the minute

The time input has no seconds and fromDateTimeInputs floors to :00, so an
event logged at "now" was stored up to ~59s in the past — the big-clock
counter would jump to e.g. "0:40" the instant a sleep boundary was logged.

Track whether the user has actually touched the date/time fields (reset in
openNoteDialog and the "Now" button, set on manual change/input). When
untouched, noteDialogAt() returns the exact Date.now(); an explicitly
picked time is still parsed from the inputs (minute precision is fine there).

src/app.js

@@ -1274,6 +1274,10 @@
   let pendingType        = null;
   let notePhotoBlob      = null; // pending blob for the dialog (not yet committed)
   let notePhotoURL       = null; // current preview object URL
+  // Whether the user has manually touched the date/time fields. While false the
+  // dialog logs at the exact current millisecond rather than the minute-floored
+  // input, so a just-logged event doesn't look up to ~59s old.
+  let noteTimeEdited     = false;
 
   function clearNotePhoto() {
     notePhotoBlob = null;
@@ -1288,6 +1292,7 @@
   function openNoteDialog(type) {
     pendingType = type;
     noteInput.value = "";
+    noteTimeEdited = false;
     const now = Date.now();
     noteDate.value = toDateInput(now);
     noteTime.value = toTimeInput(now);
@@ -1301,6 +1306,9 @@
   }
 
   function noteDialogAt() {
+    // Untouched time → stamp the exact current instant (sub-minute accurate).
+    // Once the user picks a time, honor the input (minute precision is fine).
+    if (!noteTimeEdited) return Date.now();
     const parsed = fromDateTimeInputs(noteDate.value, noteTime.value);
     return Number.isFinite(parsed) ? parsed : Date.now();
   }
@@ -1309,6 +1317,13 @@
     const now = Date.now();
     noteDate.value = toDateInput(now);
     noteTime.value = toTimeInput(now);
+    noteTimeEdited = false; // "Now" means log at the current instant again
+  });
+
+  [noteDate, noteTime].forEach(el => {
+    const markEdited = () => { noteTimeEdited = true; };
+    el.addEventListener("change", markEdited);
+    el.addEventListener("input", markEdited);
   });
 
   notePhotoBtn.addEventListener("click", () => notePhotoInput.click());