Fix Garmin intensity minutes and add user-configurable phase goals

- Apply 2x multiplier for vigorous intensity minutes (matches Garmin)
- Use calendar week (Mon-Sun) instead of trailing 7 days for intensity
- Add HRV yesterday fallback when today's data returns empty
- Add user-configurable phase intensity goals with new defaults:
  - Menstrual: 75, Follicular: 150, Ovulation: 100
  - Early Luteal: 120, Late Luteal: 50
- Update garmin-sync and today routes to use user-specific phase limits

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

src/app/api/garmin/tokens/route.test.ts

@@ -60,6 +60,11 @@ describe("POST /api/garmin/tokens", () => {
     notificationTime: "07:30",
     timezone: "America/New_York",
     activeOverrides: [],
+    intensityGoalMenstrual: 75,
+    intensityGoalFollicular: 150,
+    intensityGoalOvulation: 100,
+    intensityGoalEarlyLuteal: 120,
+    intensityGoalLateLuteal: 50,
     created: new Date("2024-01-01"),
     updated: new Date("2025-01-10"),
   };
@@ -276,6 +281,11 @@ describe("DELETE /api/garmin/tokens", () => {
     notificationTime: "07:30",
     timezone: "America/New_York",
     activeOverrides: [],
+    intensityGoalMenstrual: 75,
+    intensityGoalFollicular: 150,
+    intensityGoalOvulation: 100,
+    intensityGoalEarlyLuteal: 120,
+    intensityGoalLateLuteal: 50,
     created: new Date("2024-01-01"),
     updated: new Date("2025-01-10"),
   };