chore(guards): give the linear-fit guard a match floor and keep SQL out of the i18n scan

The linear-fit guard floored only its walk; it now also requires the
implementation's call sites it expects. The per-type readings query
aliased its driving relation t, which the i18n call-site scanner read as a
translation call; it is mt now, as in readLatestEver.

src/__tests__/linear-fit-single-implementation-guard.test.ts

@@ -57,6 +57,14 @@ describe("one least-squares line", () => {
         ),
     );
     expect(offenders).toEqual([]);
+    // The six readers now call the implementation: a sweep that finds fewer
+    // call sites read the wrong tree or lost one.
+    const callers = files.filter((file) =>
+      /\b(?:linearFit|fitFromSums|trendLineByTime)\s*\(/.test(
+        stripComments(readFileSync(join(SRC, file), "utf8")),
+      ),
+    );
+    expect(callers.length).toBeGreaterThanOrEqual(7);
     // The implementation itself matches, so the sweep read real files.
     expect(
       HAND_ROLLED_SLOPE.test(

src/lib/insights/recent-readings.ts

@@ -70,7 +70,9 @@ export async function readRecentReadings(
  * the multi-metric overview. It read the newest 5 000 rows across all types
  * at once, so a dense stream (pulse every few minutes) filled the whole read
  * within days and every other type fell out of the overview. One index
- * descent per type now bounds each type on its own.
+ * descent per type now bounds each type on its own. The driving relation is
+ * aliased `mt`, the way `readLatestEver` aliases it, so the i18n call-site
+ * scanner does not read the SQL as a translation call.
  */
 export async function readLatestReadingsPerType(
   userId: string,
@@ -81,13 +83,13 @@ export async function readLatestReadingsPerType(
   const rows = await prisma.$queryRaw<
     Array<{ type: MeasurementType; value: number; measured_at: Date }>
   >`
-    SELECT t."type" AS "type", x."value", x."measured_at"
-    FROM unnest(${[...types]}::text[]) AS t("type")
+    SELECT mt."type" AS "type", x."value", x."measured_at"
+    FROM unnest(${[...types]}::text[]) AS mt("type")
     CROSS JOIN LATERAL (
       SELECT m."value", m."measured_at"
       FROM measurements m
       WHERE m."user_id" = ${userId}
-        AND m."type" = t."type"::measurement_type
+        AND m."type" = mt."type"::measurement_type
         AND m."deleted_at" IS NULL
       ORDER BY m."measured_at" DESC
       LIMIT ${perType}