fix(insights): scan one discovery matrix from every correlation surface

Four surfaces assembled the correlation-discovery matrix and three carried a
different channel set. The Coach `get_correlations` tool had neither the
environmental-exposure channels nor the custom-metric ones, so asking it
whether air pressure relates to your sleep met a matrix the pair had never
been in. Its own file header said the opposite - "the SAME full-matrix scan
the route runs" - and had said it since the weather channels arrived in
v1.25. The period narrative was missing those two families and the
compliance / symptom pair on top.

`src/lib/insights/discovery-matrix.ts` is now the one place a matrix is
built. v1.30.3 hoisted the fetch discipline into a shared module for exactly
this reason and left the assembly duplicated behind; this finishes it. The
route, the per-metric card, the Coach tool and the period narrative all call
`assembleDiscoveryMatrix` and get the same families. What still differs is
declared as an option with its reason at the declaration: the measurement
read mode (a read-cost choice, left per surface), the extra metric types the
narrative's delta beat needs, and the RATED mood factors.

Mood factors stay on the narrative alone. That capture kind is frozen, the
two surfaces that persist a discovered pair write its channel key into a
plaintext column, and a custom factor's key is an opaque id - so admitting
them elsewhere is a decision about what to ask, not a parity fix.

Restore the per-metric filter on the assessment card's relations. It was
written in place of the pattern-dismissal filter rather than chained with it,
so a weight card's prompt had been receiving every surviving pair in the
record while the function name, the docstring and the early-return guard all
still said one metric.

`discovery-matrix-guard.test.ts` freezes who may fetch a channel, who may
construct one, and who may scan. Each matcher asserts a non-zero match count,
so a matcher that has stopped matching fails rather than agreeing with the
allowlist.

The statistics are untouched - same Pearson, same exact p-value, same
Benjamini-Hochberg, same floors. The Coach's family is larger now, which is
the point: it is corrected over the same family the insights page is.

src/app/api/insights/correlations/route.ts

@@ -11,9 +11,12 @@
  * causal.
  *
  * Reads daily series bounded to a trailing window, day-keyed in the user's
- * display timezone (late-night readings mis-bucket under UTC). Pure compute
- * lives in `src/lib/insights/correlation-discovery.ts`; this route only
- * fetches + day-keys + responds. No LLM, no narrative, no cache table.
+ * display timezone (late-night readings mis-bucket under UTC). The channel set
+ * comes from `src/lib/insights/discovery-matrix.ts`, the one assembler every
+ * discovery surface shares; the pure compute lives in
+ * `src/lib/insights/correlation-discovery.ts`. This route only asks for the
+ * matrix, scans it, persists the pattern decisions and responds. No LLM, no
+ * narrative, no cache table.
  */
 import { apiHandler, requireRecordAuth } from "@/lib/api-handler";
 import { apiError, apiSuccess } from "@/lib/api-response";
@@ -25,34 +28,19 @@ import { requireModuleEnabled } from "@/lib/modules/gate";
 import { resolveServerLocale } from "@/lib/i18n/server-locale";
 import { prisma } from "@/lib/db";
 import { wallClockInTz } from "@/lib/tz/wall-clock";
-import type { MeasurementType } from "@/generated/prisma/client";
 import {
   discoverCorrelations,
   discoverEmergingCorrelations,
   discoverLabOutcomeCorrelations,
-  discoveryMeasurementTypes,
-  DISCOVERY_BEHAVIOURS,
-  DISCOVERY_OUTCOMES,
   EARLY_WINDOW_DAYS,
-  MEDICATION_COMPLIANCE_CHANNEL_KEY,
-  SYMPTOM_SEVERITY_CHANNEL_KEY,
-  type DailySeriesPoint,
-  type NamedSeries,
 } from "@/lib/insights/correlation-discovery";
 import {
   decisionForEvidence,
   PATTERN_FAMILIES,
   syncAcceptedPatterns,
 } from "@/lib/insights/correlation-patterns";
-import {
-  fetchComplianceSeries,
-  fetchCustomMetricBehaviourSeries,
-  fetchEnvironmentSeries,
-  fetchLabDraws,
-  fetchMeasurementDailySeriesTiered,
-  fetchMoodWindowSeries,
-  fetchSymptomSeries,
-} from "@/lib/insights/correlation-channel-series";
+import { assembleDiscoveryMatrix } from "@/lib/insights/discovery-matrix";
+import { fetchLabDraws } from "@/lib/insights/correlation-channel-series";
 
 export const dynamic = "force-dynamic";
 
@@ -125,85 +113,22 @@ async function buildCorrelationsResponse(
   const now = new Date();
   const since = new Date(now.getTime() - WINDOW_DAYS * MS_PER_DAY);
 
-  // Non-MeasurementType channels are backed by other models, not measurements —
-  // MOOD (MoodEntry), MEDICATION_COMPLIANCE (the dose-history ledger), and
-  // SYMPTOM_SEVERITY (the illness day-log). `discoveryMeasurementTypes` drops
-  // them so the `type IN (...)` query carries only real enum values; each is
-  // built from its own source below and folded into the series.
-  const behaviourTypes = discoveryMeasurementTypes(
-    DISCOVERY_BEHAVIOURS,
-  ) as MeasurementType[];
-  const outcomeTypes = discoveryMeasurementTypes(
-    DISCOVERY_OUTCOMES,
-  ) as MeasurementType[];
-
-  // Rollup read-swap for the measurement channels: eligible spot channels
-  // read their per-day means from the DAY rollup tier, with per-channel
-  // fallback to the raw `fetchMeasurementWindowSeries` path on any miss
-  // (coverage gap, far-from-UTC profile tz, sleep / cumulative grain) —
-  // see `fetchMeasurementDailySeriesTiered` for the full parity contract.
-  // The SWR cache cell above stays in front of this read: the swap only
-  // lowers the cost of a cache MISS, it does not replace the cache.
-  const [measurementDaily, moodWindow] = await Promise.all([
-    fetchMeasurementDailySeriesTiered(userId, tz, since, [
-      ...behaviourTypes,
-      ...outcomeTypes,
-    ]),
-    fetchMoodWindowSeries(userId, tz, since),
-  ]);
-  const { measurementsCapped } = measurementDaily;
-  const { moodDaily, moodCapped } = moodWindow;
-
-  // v1.21.0 (FDREXTEND) — build the two non-measurement, non-mood channels from
-  // their own sources. Each degrades to an empty series when the user has no
-  // data, so the discovery loop drops the channel (it cannot clear n ≥ 20).
-  // v1.22 — lab draws (for the labs ↔ outcome pass) fetch alongside.
-  const [
-    complianceSeries,
-    symptomSeries,
-    labDraws,
-    environmentSeries,
-    customMetricSeries,
-  ] = await Promise.all([
-    fetchComplianceSeries(userId, tz, since),
-    fetchSymptomSeries(userId, tz, since),
+  // The channel set comes from the one assembler every discovery surface
+  // shares (`discovery-matrix.ts`) — this route, the per-metric card, the Coach
+  // tool and the period narrative all scan the same matrix by construction.
+  // `"tiered"` puts the eligible measurement channels on the DAY rollup
+  // read-swap, with per-channel fallback to the raw path on any miss (coverage
+  // gap, far-from-UTC profile tz, sleep / cumulative grain). The SWR cache cell
+  // above stays in front of this read: the swap only lowers the cost of a cache
+  // MISS, it does not replace the cache.
+  //
+  // v1.22 — lab draws (for the labs ↔ outcome pass) fetch alongside; they feed
+  // a different pass over a different grain, so they are not matrix channels.
+  const [matrix, labDraws] = await Promise.all([
+    assembleDiscoveryMatrix(userId, { tz, since, fetchMode: "tiered" }),
     fetchLabDraws(userId, tz, since),
-    // v1.25 (W-ENV) — environmental-exposure behaviour channels (weather /
-    // daylight). Empty when the module is off / no home set, so the channels
-    // degrade to absent. The module gate is implicit: no rows ⇒ no channels.
-    fetchEnvironmentSeries(userId, since),
-    fetchCustomMetricBehaviourSeries(userId, tz, since),
   ]);
-
-  const points = (key: string): DailySeriesPoint[] =>
-    key === "MOOD" ? moodDaily : (measurementDaily.byType.get(key) ?? []);
-
-  const series: NamedSeries[] = [];
-  for (const key of DISCOVERY_BEHAVIOURS) {
-    if (key === MEDICATION_COMPLIANCE_CHANNEL_KEY) {
-      series.push(complianceSeries);
-    } else if (key === SYMPTOM_SEVERITY_CHANNEL_KEY) {
-      series.push({ ...symptomSeries, role: "behaviour" });
-    } else {
-      series.push({ key, role: "behaviour", points: points(key) });
-    }
-  }
-  for (const key of DISCOVERY_OUTCOMES) {
-    if (key === SYMPTOM_SEVERITY_CHANNEL_KEY) {
-      series.push({ ...symptomSeries, role: "outcome" });
-    } else {
-      series.push({ key, role: "outcome", points: points(key) });
-    }
-  }
-  // v1.25 (W-ENV) — fold the environmental-exposure behaviour channels in. They
-  // pair (lag D → D+1) against every outcome above; the n ≥ 20 / FDR / effect-
-  // size gates apply unchanged, so a thin weather series degrades to absent.
-  for (const envSeries of environmentSeries) {
-    series.push(envSeries);
-  }
-  for (const customSeries of customMetricSeries) {
-    series.push(customSeries);
-  }
+  const { series, diagnostics } = matrix;
 
   const result = discoverCorrelations(series, { locale });
 
@@ -278,15 +203,15 @@ async function buildCorrelationsResponse(
       // half of the window may be thin.
       // The cap can only apply to raw-path channels — rollup-served
       // channels read one row per day per source and cannot reach it.
-      measurements_capped: measurementsCapped,
+      measurements_capped: diagnostics.measurementsCapped,
       // Rollup read-swap reach: how many measurement channels rode the DAY
       // rollup tier on this build (the rest took the raw fallback path).
-      measurement_rollup_channels: measurementDaily.rollupTypes.length,
-      mood_entries_capped: moodCapped,
+      measurement_rollup_channels: diagnostics.rollupTypes.length,
+      mood_entries_capped: diagnostics.moodCapped,
       // FDREXTEND — per-channel day-counts so a dashboard can see whether the
       // two sparse new channels reached the n ≥ 20 floor or degraded to absent.
-      compliance_days: complianceSeries.points.length,
-      symptom_days: symptomSeries.points.length,
+      compliance_days: diagnostics.complianceDays,
+      symptom_days: diagnostics.symptomDays,
       // v1.22 — early-detection + labs reach.
       emerging: emerging.emerging.length,
       emerging_window_days: emerging.windowDays,
@@ -295,15 +220,9 @@ async function buildCorrelationsResponse(
       // v1.25 (W-ENV) — env channel reach (sum of stored daily points across
       // the exposure channels) so a dashboard can see whether weather was
       // available for the scan.
-      environment_days: environmentSeries.reduce(
-        (sum, s) => sum + s.points.length,
-        0,
-      ),
-      custom_metric_channels: customMetricSeries.length,
-      custom_metric_days: customMetricSeries.reduce(
-        (sum, channel) => sum + channel.points.length,
-        0,
-      ),
+      environment_days: diagnostics.environmentDays,
+      custom_metric_channels: diagnostics.customMetricChannels,
+      custom_metric_days: diagnostics.customMetricDays,
     },
   });