feat(healthchat): paint the subtle gradient in brand blue

ElementX/Sources/AppHooks/HealthChat/HealthChatCompoundHook.swift

@@ -28,6 +28,7 @@ struct HealthChatCompoundHook: CompoundHookProtocol {
             \.textActionAccent,
             \.textLinkExternal,
             \.borderInteractivePrimary,
+            \.borderAccentPrimary,
             \.textBadgeAccent
         ]
         let solidUIColorTokens: [KeyPath<CompoundUIColorTokens, UIColor> & Sendable] = [
@@ -39,6 +40,7 @@ struct HealthChatCompoundHook: CompoundHookProtocol {
             \.textActionAccent,
             \.textLinkExternal,
             \.borderInteractivePrimary,
+            \.borderAccentPrimary,
             \.textBadgeAccent
         ]
         for keyPath in solidColorTokens {
@@ -63,6 +65,19 @@ struct HealthChatCompoundHook: CompoundHookProtocol {
             colors.override(keyPath, with: Color(brand))
         }
         
+        // Subtle gradient (home screen bloom, highlighted timeline item) → brand blue fading out,
+        // at the opacities Compound uses for its green stops. Stop 6 stays transparent.
+        let subtleGradientTokens: [KeyPath<CompoundColorTokens, Color>] = [
+            \.gradientSubtleStop1,
+            \.gradientSubtleStop2,
+            \.gradientSubtleStop3,
+            \.gradientSubtleStop4,
+            \.gradientSubtleStop5
+        ]
+        for (keyPath, opacity) in zip(subtleGradientTokens, [0.41, 0.23, 0.11, 0.06, 0.03]) {
+            colors.override(keyPath, with: Color(brand).opacity(opacity))
+        }
+        
         // Subtle accent backgrounds (paired with accent-coloured foregrounds) → brand tint.
         let tintColorTokens: [KeyPath<CompoundColorTokens, Color>] = [
             \.bgAccentSelected,