refactor: fix active hours calculation with monotonic cycle model

Previous implementation had discontinuities at day boundaries. New
cycle-based approach (2 AM sleep start) provides continuous, testable
active hour tracking.

package.json

@@ -0,0 +1,6 @@
+{
+  "dependencies": {},
+  "devDependencies": {
+    "chalk": "^5.6.2"
+  }
+}