Drop unimported re-exports from the derived-metrics barrel

The barrel mirrored every export under src/lib/insights/derived. Of the
124 lines, 101 had no importer: consumers and per-metric tests reach for
the concrete module (./sleep-score, ./trajectory, …) directly. Keep the
cross-cutting surface — registry, dispatcher, baseline loader, and the
value shapes outside consumers read — and say in the header that the
barrel is not a mirror, so the next addition needs a consumer first.

Definitions are untouched; only the re-export lines go.

src/lib/insights/derived/index.ts

@@ -1,185 +1,47 @@
 /**
  * v1.10.0 — public barrel for the derived-metrics layer.
  *
- * The one module every consumer imports from. Append-only per wave —
- * Wave 1 exports the foundation (`Derived<T>` + coverage builders +
- * registry + norms + the flagship baseline engine + the route
- * dispatcher); W2/W3 append their per-metric engines (`fitness-age`,
- * `vascular-age`, `sleep-score`, `readiness`) here.
+ * Carries the cross-cutting surface: the registry (which metrics exist and
+ * how they are archetyped), the route dispatcher, the baseline profile
+ * loader, and the handful of per-metric compute engines and value shapes
+ * that consumers outside this directory actually reach for.
  *
- * Re-exports the client-safe types/coverage builders and the
- * server-only compute engines from one place; consumers import only what
- * they need. (A `"use client"` component must value-import only from
- * `./types` + `./coverage` + `./registry` — those are server-import-free.
- * The route + server consumers may import the engines below.)
+ * It is deliberately NOT a mirror of every export under `./`. The per-metric
+ * scoring helpers, their `*Opts` / `*Band` types and the sub-score weights are
+ * imported from their concrete module (`./sleep-score`, `./trajectory`, …) by
+ * the code and tests that use them; re-exporting them here only produced lines
+ * nothing imported. Add a line below when an outside consumer appears, not in
+ * anticipation of one.
+ *
+ * A `"use client"` component must value-import only from `./types`,
+ * `./coverage` and `./registry` — those are server-import-free. The route and
+ * server consumers may import the engines below.
  */
 
-// ── client-safe contract (types + pure builders + metadata) ──────────
-export type {
-  Derived,
-  DerivedOk,
-  DerivedInsufficient,
-  DerivedCoverage,
-  DerivedConfidence,
-  DerivedConfidenceBand,
-  DerivedProvenance,
-  DerivedProvenanceSource,
-} from "./types";
+// ── client-safe contract ─────────────────────────────────────────────
 export { isDerivedOk } from "./types";
 
-export {
-  deriveCoverage,
-  buildOk,
-  buildInsufficient,
-  scoreToBand,
-  nowProvenanceTimestamp,
-} from "./coverage";
-export type { DeriveCoverageArgs } from "./coverage";
-
 export {
   DERIVED_METRIC_IDS,
-  VITALS_BASELINE_TYPES,
   TRAJECTORY_TYPES,
-  SAME_TIME_BASELINE_TYPES,
-  SAME_TIME_BASELINE_WINDOW_DAYS,
-  SAME_TIME_BASELINE_MIN_HISTORY_DAYS,
   isDerivedMetricId,
-  getDerivedMetricMeta,
-  isVitalsBaselineType,
-  isTrajectoryType,
-  isSameTimeBaselineType,
 } from "./registry";
-export type {
-  DerivedMetricId,
-  DerivedMetricMeta,
-  DerivedArchetype,
-} from "./registry";
-
-export {
-  lookupNormalRange,
-  hasSharpenedNorm,
-  predictSixMinuteWalkDistance,
-} from "./norms";
-export type { NormRange, NormSex } from "./norms";
+export type { DerivedMetricId } from "./registry";
 
 // ── server-only compute engines (do NOT value-import from a client component) ──
-export {
-  computeVitalsBaseline,
-  loadBaselineProfile,
-  buildBaselineBand,
-  median,
-  medianAbsoluteDeviation,
-} from "./baseline";
-export type {
-  VitalsBaselineValue,
-  VitalsBaselineOpts,
-  BaselineProfile,
-} from "./baseline";
+export { loadBaselineProfile } from "./baseline";
+export type { BaselineProfile } from "./baseline";
 
 export { computeDerivedMetric } from "./dispatch";
-export type { DerivedComputeArgs } from "./dispatch";
 
-// ── W2b vitals tier: passthrough re-frames + derived bands ───────────
-export {
-  computeFitnessAge,
-  placeVo2Band,
-  fitnessAgeDeltaYears,
-} from "./fitness-age";
-export type { FitnessAgeValue, FitnessBand } from "./fitness-age";
+export type { SleepScoreValue } from "./sleep-score";
 
-export {
-  computeSixMinuteWalkBand,
-  placeSixMinuteWalkBand,
-} from "./six-minute-walk";
-export type { SixMinuteWalkValue, SixMinuteWalkBand } from "./six-minute-walk";
+export { computeReadiness } from "./readiness";
+export type { ReadinessValue, ReadinessComponentKey } from "./readiness";
 
-export { computeVascularAgeDelta, placeVascularBand } from "./vascular-age";
-export type { VascularAgeDeltaValue, VascularBand } from "./vascular-age";
+export { computeCoincidentDeviation } from "./coincident-deviation";
 
-export { computeHrvBalance, placeHrvBalance } from "./hrv-balance";
-export type { HrvBalanceValue, HrvBalanceBand } from "./hrv-balance";
+export type { WellnessScoreValue } from "./wellness-scores";
 
-export { computeBmi, classifyBmi } from "./bmi";
-export type { BmiValue, BmiBand, BmiCategory } from "./bmi";
-// ── W3 composites (server-only compute engines) ──────────────────────
-export {
-  computeSleepScore,
-  blendSleepSubScores,
-  reconstructNights,
-  sleepNeedMinutes,
-  scoreSufficiency,
-  scoreEfficiency,
-  scoreComposition,
-  scoreConsistency,
-  scoreTiming,
-  SLEEP_SUBSCORE_WEIGHTS,
-} from "./sleep-score";
-export type {
-  SleepScoreValue,
-  SleepScoreOpts,
-  SleepSubScore,
-  SleepSubScoreKey,
-  NightSummary,
-} from "./sleep-score";
-
-export {
-  computeReadiness,
-  blendReadinessComponents,
-  scoreDeviation,
-  READINESS_WEIGHTS,
-  READINESS_MIN_COMPONENTS,
-} from "./readiness";
-export type {
-  ReadinessValue,
-  ReadinessOpts,
-  ReadinessComponent,
-  ReadinessComponentKey,
-} from "./readiness";
-
-export {
-  computeCoincidentDeviation,
-  classifyDeviation,
-  COINCIDENT_FIRE_THRESHOLD,
-  COINCIDENT_MIN_BANDS,
-} from "./coincident-deviation";
-export type {
-  CoincidentDeviationValue,
-  CoincidentDeviationOpts,
-  VitalDeviation,
-} from "./coincident-deviation";
-
-// ── persisted nightly wellness scores (passthrough read) ─────────────
-export {
-  computeWellnessScore,
-  bandWellnessScore,
-  WELLNESS_SCORE_TYPES,
-} from "./wellness-scores";
-export type {
-  WellnessScoreValue,
-  WellnessScoreBand,
-  WellnessScoreType,
-  WellnessScoreOpts,
-} from "./wellness-scores";
-
-// ── v1.11.0 (Epic B, Pillar 3) forecasting engine (server-only) ──────
-export {
-  computeTrajectory,
-  fitOls,
-  predictionIntervalHalfWidth,
-  TRAJECTORY_MIN_R2,
-  TRAJECTORY_MIN_HISTORY_DAYS,
-} from "./trajectory";
-export type {
-  TrajectoryValue,
-  TrajectoryPoint,
-  TrajectoryOpts,
-  OlsFit,
-} from "./trajectory";
-
-// ── v1.34.0 same-time baseline for cumulative metrics (server-only) ──
-export { computeSameTimeBaseline } from "./same-time-baseline";
-export type {
-  SameTimeBaselineValue,
-  SameTimeBaselineOpts,
-  SameTimeBand,
-} from "./same-time-baseline";
+export { computeTrajectory } from "./trajectory";
+export type { TrajectoryValue } from "./trajectory";