Add mood-specific selectable chip answers to guided reflection flow

Reduces friction in the guided reflection by offering predefined tappable
chip answers tailored to each mood category's therapeutic framework:
- Positive (Behavioral Activation): savoring emotions + reinforcing actions
- Neutral (ACT Cognitive Defusion): ambivalent feelings + defusion reframes + values
- Negative (CBT Thought Record): automatic negative thoughts + compassionate reframes + grounding actions

Chips appear between the question and text editor. Tapping toggles selection
and auto-fills the text field. "More" expander reveals additional options.
Free text always remains available alongside chips.

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

Shared/AccessibilityIdentifiers.swift

@@ -70,6 +70,11 @@ enum AccessibilityID {
         static func questionLabel(step: Int) -> String {
             "guided_reflection_question_\(step)"
         }
+        static let chipGrid = "guided_reflection_chip_grid"
+        static let chipMoreButton = "guided_reflection_chip_more"
+        static func chip(label: String) -> String {
+            "guided_reflection_chip_\(label)"
+        }
     }
 
     // MARK: - Settings