fix(demo): stamp the baked briefing so the readers serve it

Every briefing reader serves `dailyBriefing` only when the payload's
`briefingGeneratedAt` falls on the reader's today. The demo seed wrote the
comprehensive payload without that stamp and without the language tag, so
on a fresh seed the advisor read returned no briefing, the dashboard
snapshot stayed "preparing", and a warm was enqueued that can only fail
against the placeholder key. The /insights card sat empty while the hero
said "Updated today".

The seed now writes the cache the way a generation does: the payload
stamped through `withBriefingGeneratedAt`, the cache stamp from the same
instant, and the `en` tag. The baked paragraph drops its "Good morning"
opener, since the hero already greets by the hour.

The hero's freshness caption dates the subtitle, so it now shows only
when the subtitle is a briefing. The cache stamp also moves when a warm
keeps yesterday's text, which the read then withholds; the caption then
sat under the generic fallback sentence.

`seed()` is exported behind a main-module guard, and an integration test
runs the real seed and reads its output back through the advisor read,
the dashboard snapshot, the status cards and the period narratives.

scripts/seed-demo.ts

@@ -78,6 +78,8 @@
 
 import { Buffer } from "node:buffer";
 import { createHash } from "node:crypto";
+import { resolve } from "node:path";
+import { fileURLToPath } from "node:url";
 
 import pg from "pg";
 import { encryptToBytes } from "../src/lib/ai/coach/bytes-codec";
@@ -88,6 +90,7 @@ import {
   getKeyFingerprint,
 } from "../src/lib/crypto";
 import { ENVIRONMENT_LOCATION_AAD } from "../src/lib/crypto/encrypted-columns";
+import { withBriefingGeneratedAt } from "../src/lib/insights/briefing-generated-at";
 import { sealInsightsCachedText } from "../src/lib/insights/cached-text-cipher";
 import {
   DEFAULT_CHART_OVERLAY_PREFS,
@@ -416,7 +419,11 @@ function daylightHours(lat: number, doy: number): number {
 
 // ── Main ─────────────────────────────────────────
 
-async function seed() {
+/**
+ * Seed the demo tenant. Exported so an integration test can run the real
+ * seed and read its output back through the app's own readers.
+ */
+export async function seed() {
   const client = await pool.connect();
 
   try {
@@ -3369,11 +3376,15 @@ async function seed() {
     const bakedProvider = "anthropic";
 
     // ── Comprehensive insight + daily briefing ──
-    // Stored sealed on users.insights_cached_text_encrypted (JSON). The GET
-    // read opens and parses it and
-    // returns it as-is; setting insights_cached_at = NOW() keeps it inside the
-    // 24 h freshness window for the dashboard-snapshot briefing path. The shape
-    // is the union of insightResultSchema (summary / findings / correlations /
+    // Stored sealed on users.insights_cached_text_encrypted (JSON), written
+    // the way a generation writes it (`briefing-request/commit.ts`): the
+    // payload stamped with its generation moment, the cache stamp, and the
+    // language tag. Every briefing reader serves `dailyBriefing` only when
+    // that `briefingGeneratedAt` falls on the reader's today, so a payload
+    // without it reads as text of unknown age: the advisor card and the
+    // dashboard headline stay empty and a warm is asked for, which on the
+    // demo can only fail against the placeholder key. The shape is the union
+    // of insightResultSchema (summary / findings / correlations /
     // recommendations / dataQuality / disclaimer / classification) and the
     // richer optional blocks the dashboard validates (dailyBriefing with
     // paragraph + signalsOfDay + keyFindings, trendAnnotations).
@@ -3461,8 +3472,10 @@ async function seed() {
         "This is a reasoned observation of your own data, not medical advice " +
         "or a diagnosis. Discuss any concerns with your doctor.",
       dailyBriefing: {
+        // No salutation: the hero above it already greets by the hour, and
+        // a demo filmed in the evening read "Good evening" over "Good morning".
         paragraph:
-          "Good morning. Today's picture is a calm one: your most recent " +
+          "Today's picture is a calm one: your most recent " +
           "blood pressure sits comfortably in the optimal band, resting heart " +
           "rate is low, and last night's sleep landed right around your " +
           "target. Weight is holding at its new steady place and your mood " +
@@ -3552,10 +3565,12 @@ async function seed() {
       },
     };
 
+    const briefingWrittenAt = new Date();
     await client.query(
       `UPDATE users
          SET insights_cached_text_encrypted = $2,
-             insights_cached_at = NOW(),
+             insights_cached_at = $5,
+             insights_cached_locale = 'en',
              insights_snapshot_hash = $3,
              insights_briefing_reroll_date = $4
        WHERE id = $1`,
@@ -3563,7 +3578,11 @@ async function seed() {
         userId,
         // Sealed like every write since v1.43.7.
         Buffer.from(
-          sealInsightsCachedText(JSON.stringify(comprehensiveInsight)),
+          sealInsightsCachedText(
+            JSON.stringify(
+              withBriefingGeneratedAt(comprehensiveInsight, briefingWrittenAt),
+            ),
+          ),
         ),
         // A stable fingerprint. The 24 h cache window keeps the row fresh on
         // its own; this value just has to be present + non-null so a
@@ -3573,6 +3592,7 @@ async function seed() {
         // Mark today's briefing re-roll as already done so the once-per-day
         // re-roll path is a no-op (it would fail against the placeholder key).
         todayKey,
+        briefingWrittenAt,
       ],
     );
 
@@ -3841,4 +3861,9 @@ async function seed() {
   }
 }
 
-seed();
+if (
+  process.argv[1] &&
+  resolve(process.argv[1]) === resolve(fileURLToPath(import.meta.url))
+) {
+  seed();
+}