Add AI-powered mental wellness features: Reflection Companion, Pattern Tags, Weekly Digest

Three new Foundation Models features to deepen user engagement with mental wellness:

1. AI Reflection Companion — personalized feedback after completing guided reflections,
   referencing the user's actual words with personality-pack-adapted tone
2. Mood Pattern Tags — auto-extracts theme tags (work, family, stress, etc.) from notes
   and reflections, displayed as colored pills on entries
3. Weekly Emotional Digest — BGTask-scheduled Sunday digest with headline, summary,
   highlight, and intention; shown as card in Insights tab with notification

All features: on-device (zero cost), premium-gated, iOS 26+ with graceful degradation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Shared/Models/AIReflectionFeedback.swift

@@ -0,0 +1,26 @@
+//
+//  AIReflectionFeedback.swift
+//  Reflect
+//
+//  @Generable model for AI-powered reflection feedback after guided reflection completion.
+//
+
+import Foundation
+import FoundationModels
+
+/// AI-generated personalized feedback after completing a guided reflection
+@available(iOS 26, *)
+@Generable
+struct AIReflectionFeedback: Equatable {
+    @Guide(description: "A warm, specific affirmation of what the user did well in their reflection (1 sentence)")
+    var affirmation: String
+
+    @Guide(description: "An observation connecting something the user wrote to a meaningful pattern or insight (1 sentence)")
+    var observation: String
+
+    @Guide(description: "A brief, actionable takeaway the user can carry forward (1 sentence)")
+    var takeaway: String
+
+    @Guide(description: "SF Symbol name for the feedback icon (e.g., sparkles, heart.fill, leaf.fill, star.fill)")
+    var iconName: String
+}