Update Neon colors and show color circles in theme picker

- Update NeonMoodTint to use synthwave colors matching Neon voting style
  (cyan, lime, yellow, orange, magenta)
- Replace text label with 5 color circles in theme preview Colors row
- Remove unused textColor customization code and picker views
- Add .id(moodTint) to Month/Year views for color refresh
- Clean up various unused color-related code

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Shared/Persisence/ExtensionDataProvider.swift

@@ -174,9 +174,12 @@ final class ExtensionDataProvider {
     ///   - date: The date for the entry
     ///   - entryType: The source of the entry (widget, watch, etc.)
     func add(mood: Mood, forDate date: Date, entryType: EntryType) {
-        // Delete existing entry for this date if present
-        if let existing = getEntry(byDate: date) {
-            modelContext.delete(existing)
+        // Delete ALL existing entries for this date (handles duplicates)
+        let existing = getAllEntries(byDate: date)
+        for entry in existing {
+            modelContext.delete(entry)
+        }
+        if !existing.isEmpty {
             try? modelContext.save()
         }
 
@@ -199,6 +202,21 @@ final class ExtensionDataProvider {
         }
     }
 
+    /// Get ALL entries for a specific date (not just the first one)
+    func getAllEntries(byDate date: Date) -> [MoodEntryModel] {
+        let startDate = Calendar.current.startOfDay(for: date)
+        let endDate = Calendar.current.date(byAdding: .day, value: 1, to: startDate)!
+
+        let descriptor = FetchDescriptor<MoodEntryModel>(
+            predicate: #Predicate { entry in
+                entry.forDate >= startDate && entry.forDate <= endDate
+            },
+            sortBy: [SortDescriptor(\.forDate, order: .forward)]
+        )
+
+        return (try? modelContext.fetch(descriptor)) ?? []
+    }
+
     /// Invalidate cached container (call when data might have changed)
     func invalidateCache() {
         _container = nil