refactor(cycle): wire the phase-correlation card into the insights tab

The cycle insights tab rendered an empty placeholder while the phase-contrast
card + its `/api/cycle/insights` feed sat unused. Wire them together: a
`useCycleInsights` read drives the headline finding + the luteal-vs-follicular
crosstab on the insights tab, matching the mood-factor crosstab styling. Drops
the placeholder card + a duplicate disclaimer component in favour of the ones
already in use, and removes the unused recency/phase-result/label exports.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/cycle/types.ts

@@ -57,15 +57,6 @@ export const HISTORY_WINDOW_N = 12;
 /** §1 — need ≥2 completed cycles for a real (non-priors) prediction. */
 export const MIN_CYCLES_TO_PREDICT = 2;
 
-/** §1 — optional recency half-life (cycles). OFF in MVP (see below). */
-export const RECENCY_HALF_LIFE = 6;
-
-/**
- * §1 — recency weighting is OFF in the v1.15 MVP (plain median) so the TS and
- * Swift engines stay trivially identical. Flip in lockstep later.
- */
-export const RECENCY_WEIGHTING_ENABLED = false;
-
 /** §1 — floor on the robust SD so the band is never zero-width (false precision). */
 export const SIGMA_FLOOR = 1.0;
 
@@ -238,11 +229,3 @@ export interface CyclePredictionResult {
   /** Robust SD of cycle length (days), >= SIGMA_FLOOR. */
   estimatedCycleSd: number;
 }
-
-/** The phase of a single calendar date relative to its containing cycle. */
-export interface PhaseResult {
-  date: string;
-  phase: CyclePhase | null;
-  /** 1-based day-of-cycle (1 = startDate), or null if the date is outside any cycle. */
-  dayOfCycle: number | null;
-}

src/lib/query-keys.ts

@@ -514,6 +514,7 @@ export const queryKeys = {
     ["cycle", "calendar", from, to] as const,
   cycleHistory: (limit: number) => ["cycle", "history", limit] as const,
   cycleProfile: () => ["cycle", "profile"] as const,
+  cycleInsights: () => ["cycle", "insights"] as const,
 };
 
 /**