Add guided reflection flow with mood-adaptive CBT/ACT questions

Walks users through 3-4 guided questions based on mood category:
positive (great/good) gets gratitude-oriented questions, neutral
(average) gets exploratory questions, and negative (bad/horrible)
gets empathetic questions. Stored as JSON in MoodEntryModel,
integrated into PDF reports, AI summaries, and CSV export.

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

Shared/Models/AIReport.swift

@@ -36,12 +36,14 @@ struct ReportEntry {
     let mood: Mood
     let notes: String?
     let weather: WeatherData?
+    let reflection: GuidedReflection?
 
     init(from model: MoodEntryModel) {
         self.date = model.forDate
         self.mood = model.mood
         self.notes = model.notes
         self.weather = model.weatherJSON.flatMap { WeatherData.decode(from: $0) }
+        self.reflection = model.reflectionJSON.flatMap { GuidedReflection.decode(from: $0) }
     }
 }