Add color-coded calendar dots, prayer notes, and export prayer log

- Each prayer gets a consistent color derived from its ID; calendar
  dots now use those colors so you can see which prayers were covered
  at a glance, and the day-detail panel color-codes each entry too
- New Notes field on every prayer card for scripture, updates, and
  mid-prayer thoughts — separate from the answer field, freely editable
- Word export now includes Notes and Prayer Log sections for each prayer

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.css

@@ -630,6 +630,22 @@ mark.highlight {
   padding: 0.1rem 0.4rem;
 }
 
+/* Notes section */
+.notes-section {
+  display: flex;
+  flex-direction: column;
+  gap: 0.5rem;
+  padding-top: 0.75rem;
+  border-top: 1px solid var(--border);
+}
+
+.notes-text {
+  font-size: 0.93rem;
+  line-height: 1.6;
+  white-space: pre-wrap;
+  color: var(--text);
+}
+
 /* Prayer log section inside card */
 .prayed-log-section {
   display: flex;