feat(cycle): field-explainer tooltip + log-sheet i18n scaffold

Add a cycle-scoped FieldInfo affordance (a focusable, SR-reachable info
button with a 44 px touch target, mirroring the mood-explainer precedent)
and the i18n keys the redesigned log-day sheet needs: a cycle.fieldInfo.*
namespace of descriptive-only explainers (BBT, cervical mucus, ovulation
test, spotting, pregnancy/progesterone test, intercourse, protection) plus
cycle.sheet.phaseDayHeader and cycle.sheet.bbtHint, across all six locales.

messages/de.json

@@ -6345,7 +6345,9 @@
       "delete": "Löschen",
       "temperatureSection": "Temperatur & Eisprung",
       "intimacySection": "Intimität & Verhütung",
-      "testsSection": "Tests"
+      "testsSection": "Tests",
+      "phaseDayHeader": "Tag {day} · {phase}",
+      "bbtHint": "Miss sie morgens als Erstes, noch vor dem Aufstehen."
     },
     "settings": {
       "title": "Zyklus-Einstellungen",
@@ -6421,6 +6423,24 @@
       "ovulationEstimate": "Gesch. Eisprung",
       "tooltipTemp": "{temp} °C",
       "ovulationConfirmed": "Bestätigter Eisprung"
+    },
+    "fieldInfo": {
+      "bbt": "Deine Ruhetemperatur, morgens als Erstes vor dem Aufstehen gemessen. Nach dem Eisprung steigt sie leicht an (etwa 0,2–0,3 °C).",
+      "bbtLabel": "Was ist die Basaltemperatur?",
+      "mucus": "Der Ausfluss verändert sich im Zyklus – von trocken oder klebrig zu cremig, dann wässrig und spinnbar rund um die fruchtbarsten Tage.",
+      "mucusLabel": "Was ist Zervixschleim?",
+      "ovulationTest": "Ein Urintest für zu Hause, der den LH-Anstieg erkennt – den Hormonschub etwa 24–36 h vor dem Eisprung. Ein positives Ergebnis markiert die fruchtbarste Phase.",
+      "ovulationTestLabel": "Was ist ein Ovulationstest?",
+      "spotting": "Leichte Blutung außerhalb der Periode.",
+      "spottingLabel": "Was ist Schmierblutung zwischen den Perioden?",
+      "pregnancyTest": "Ergebnis eines Schwangerschaftstests (hCG) für zu Hause.",
+      "pregnancyTestLabel": "Was ist ein Schwangerschaftstest?",
+      "progesteroneTest": "Ein Test, der bestätigt, dass der Eisprung stattgefunden hat – das Progesteron steigt danach an.",
+      "progesteroneTestLabel": "Was ist ein Progesterontest?",
+      "intercourse": "Ob an diesem Tag Geschlechtsverkehr stattgefunden hat.",
+      "intercourseLabel": "Was erfasst Geschlechtsverkehr?",
+      "protected": "Ob beim Verkehr verhütet wurde.",
+      "protectedLabel": "Was bedeutet geschützt?"
     }
   },
   "cycleReminders": {

messages/en.json

@@ -6345,7 +6345,9 @@
       "clear": "None",
       "temperatureSection": "Temperature & ovulation",
       "intimacySection": "Intimacy & contraception",
-      "testsSection": "Tests"
+      "testsSection": "Tests",
+      "phaseDayHeader": "Day {day} · {phase}",
+      "bbtHint": "Take it first thing in the morning, before getting up."
     },
     "testResult": {
       "POSITIVE": "Positive",
@@ -6421,6 +6423,24 @@
       "ovulationEstimate": "Est. ovulation",
       "tooltipTemp": "{temp} °C",
       "ovulationConfirmed": "Confirmed ovulation"
+    },
+    "fieldInfo": {
+      "bbt": "Your resting temperature, taken first thing in the morning before getting up. It rises slightly (about 0.2–0.3 °C) after ovulation.",
+      "bbtLabel": "What is basal body temperature?",
+      "mucus": "Vaginal discharge changes across the cycle — from dry or sticky to creamy, then watery and egg-white-like around the most fertile days.",
+      "mucusLabel": "What is cervical mucus?",
+      "ovulationTest": "A home urine test that detects the LH surge — the hormone spike about 24–36 h before ovulation. A positive flags the most fertile window.",
+      "ovulationTestLabel": "What is an ovulation test?",
+      "spotting": "Light bleeding outside the period.",
+      "spottingLabel": "What is spotting between periods?",
+      "pregnancyTest": "Result of a home pregnancy (hCG) test.",
+      "pregnancyTestLabel": "What is a pregnancy test?",
+      "progesteroneTest": "A test confirming ovulation has occurred — progesterone rises afterward.",
+      "progesteroneTestLabel": "What is a progesterone test?",
+      "intercourse": "Whether sexual intercourse took place on this day.",
+      "intercourseLabel": "What does intercourse track?",
+      "protected": "Whether contraception was used during intercourse.",
+      "protectedLabel": "What does protected mean?"
     }
   },
   "cycleReminders": {

messages/es.json

@@ -6345,7 +6345,9 @@
       "delete": "Eliminar",
       "temperatureSection": "Temperatura y ovulación",
       "intimacySection": "Intimidad y anticoncepción",
-      "testsSection": "Pruebas"
+      "testsSection": "Pruebas",
+      "phaseDayHeader": "Día {day} · {phase}",
+      "bbtHint": "Mídela a primera hora de la mañana, antes de levantarte."
     },
     "settings": {
       "title": "Ajustes del ciclo",
@@ -6421,6 +6423,24 @@
       "ovulationEstimate": "Ovulación est.",
       "tooltipTemp": "{temp} °C",
       "ovulationConfirmed": "Ovulación confirmada"
+    },
+    "fieldInfo": {
+      "bbt": "Tu temperatura en reposo, medida a primera hora de la mañana antes de levantarte. Sube ligeramente (unos 0,2–0,3 °C) tras la ovulación.",
+      "bbtLabel": "¿Qué es la temperatura basal?",
+      "mucus": "El flujo vaginal cambia a lo largo del ciclo: de seco o pegajoso a cremoso, y luego acuoso y como clara de huevo en los días más fértiles.",
+      "mucusLabel": "¿Qué es el moco cervical?",
+      "ovulationTest": "Una prueba de orina casera que detecta el pico de LH, el aumento hormonal unas 24–36 h antes de la ovulación. Un positivo señala la ventana más fértil.",
+      "ovulationTestLabel": "¿Qué es una prueba de ovulación?",
+      "spotting": "Sangrado leve fuera de la menstruación.",
+      "spottingLabel": "¿Qué es el manchado entre periodos?",
+      "pregnancyTest": "Resultado de una prueba de embarazo casera (hCG).",
+      "pregnancyTestLabel": "¿Qué es una prueba de embarazo?",
+      "progesteroneTest": "Una prueba que confirma que ha ocurrido la ovulación: la progesterona sube después.",
+      "progesteroneTestLabel": "¿Qué es una prueba de progesterona?",
+      "intercourse": "Si hubo relaciones sexuales este día.",
+      "intercourseLabel": "¿Qué registra relaciones?",
+      "protected": "Si se usó anticoncepción durante las relaciones.",
+      "protectedLabel": "¿Qué significa protegido?"
     }
   },
   "cycleReminders": {

messages/fr.json

@@ -6345,7 +6345,9 @@
       "delete": "Supprimer",
       "temperatureSection": "Température et ovulation",
       "intimacySection": "Intimité et contraception",
-      "testsSection": "Tests"
+      "testsSection": "Tests",
+      "phaseDayHeader": "Jour {day} · {phase}",
+      "bbtHint": "Prends-la dès le matin, avant de te lever."
     },
     "settings": {
       "title": "Réglages du cycle",
@@ -6421,6 +6423,24 @@
       "ovulationEstimate": "Ovulation est.",
       "tooltipTemp": "{temp} °C",
       "ovulationConfirmed": "Ovulation confirmée"
+    },
+    "fieldInfo": {
+      "bbt": "Ta température au repos, prise dès le matin avant de te lever. Elle augmente légèrement (environ 0,2–0,3 °C) après l'ovulation.",
+      "bbtLabel": "Qu'est-ce que la température basale ?",
+      "mucus": "Les pertes vaginales évoluent au fil du cycle — de sèches ou collantes à crémeuses, puis aqueuses et comme du blanc d'œuf autour des jours les plus fertiles.",
+      "mucusLabel": "Qu'est-ce que la glaire cervicale ?",
+      "ovulationTest": "Un test urinaire à domicile qui détecte le pic de LH — la montée hormonale environ 24–36 h avant l'ovulation. Un test positif signale la période la plus fertile.",
+      "ovulationTestLabel": "Qu'est-ce qu'un test d'ovulation ?",
+      "spotting": "Léger saignement en dehors des règles.",
+      "spottingLabel": "Qu'est-ce que le spotting entre les règles ?",
+      "pregnancyTest": "Résultat d'un test de grossesse (hCG) à domicile.",
+      "pregnancyTestLabel": "Qu'est-ce qu'un test de grossesse ?",
+      "progesteroneTest": "Un test confirmant que l'ovulation a eu lieu — la progestérone augmente ensuite.",
+      "progesteroneTestLabel": "Qu'est-ce qu'un test de progestérone ?",
+      "intercourse": "Si un rapport sexuel a eu lieu ce jour-là.",
+      "intercourseLabel": "Que suit le rapport ?",
+      "protected": "Si une contraception a été utilisée pendant le rapport.",
+      "protectedLabel": "Que signifie protégé ?"
     }
   },
   "cycleReminders": {

messages/it.json

@@ -6345,7 +6345,9 @@
       "delete": "Elimina",
       "temperatureSection": "Temperatura e ovulazione",
       "intimacySection": "Intimità e contraccezione",
-      "testsSection": "Test"
+      "testsSection": "Test",
+      "phaseDayHeader": "Giorno {day} · {phase}",
+      "bbtHint": "Misurala appena sveglia, prima di alzarti."
     },
     "settings": {
       "title": "Impostazioni del ciclo",
@@ -6421,6 +6423,24 @@
       "ovulationEstimate": "Ovulazione stim.",
       "tooltipTemp": "{temp} °C",
       "ovulationConfirmed": "Ovulazione confermata"
+    },
+    "fieldInfo": {
+      "bbt": "La tua temperatura a riposo, misurata appena sveglia prima di alzarti. Dopo l'ovulazione sale leggermente (circa 0,2–0,3 °C).",
+      "bbtLabel": "Cos'è la temperatura basale?",
+      "mucus": "Le perdite vaginali cambiano durante il ciclo — da secche o appiccicose a cremose, poi acquose e simili ad albume nei giorni più fertili.",
+      "mucusLabel": "Cos'è il muco cervicale?",
+      "ovulationTest": "Un test delle urine domestico che rileva il picco di LH — l'aumento ormonale circa 24–36 h prima dell'ovulazione. Un positivo segnala la finestra più fertile.",
+      "ovulationTestLabel": "Cos'è un test di ovulazione?",
+      "spotting": "Lieve sanguinamento al di fuori delle mestruazioni.",
+      "spottingLabel": "Cos'è lo spotting tra le mestruazioni?",
+      "pregnancyTest": "Risultato di un test di gravidanza (hCG) domestico.",
+      "pregnancyTestLabel": "Cos'è un test di gravidanza?",
+      "progesteroneTest": "Un test che conferma l'avvenuta ovulazione — il progesterone sale dopo.",
+      "progesteroneTestLabel": "Cos'è un test del progesterone?",
+      "intercourse": "Se in questo giorno ci sono stati rapporti sessuali.",
+      "intercourseLabel": "Cosa registra i rapporti?",
+      "protected": "Se durante il rapporto è stata usata la contraccezione.",
+      "protectedLabel": "Cosa significa protetto?"
     }
   },
   "cycleReminders": {

messages/pl.json

@@ -6345,7 +6345,9 @@
       "delete": "Usuń",
       "temperatureSection": "Temperatura i owulacja",
       "intimacySection": "Intymność i antykoncepcja",
-      "testsSection": "Testy"
+      "testsSection": "Testy",
+      "phaseDayHeader": "Dzień {day} · {phase}",
+      "bbtHint": "Zmierz ją rano zaraz po przebudzeniu, przed wstaniem."
     },
     "settings": {
       "title": "Ustawienia cyklu",
@@ -6421,6 +6423,24 @@
       "ovulationEstimate": "Szac. owulacja",
       "tooltipTemp": "{temp} °C",
       "ovulationConfirmed": "Potwierdzona owulacja"
+    },
+    "fieldInfo": {
+      "bbt": "Twoja temperatura spoczynkowa, mierzona rano zaraz po przebudzeniu, przed wstaniem. Po owulacji nieznacznie rośnie (o około 0,2–0,3 °C).",
+      "bbtLabel": "Czym jest temperatura podstawowa?",
+      "mucus": "Wydzielina z pochwy zmienia się w cyklu — od suchej lub lepkiej do kremowej, a następnie wodnistej i przypominającej białko jaja w najbardziej płodnych dniach.",
+      "mucusLabel": "Czym jest śluz szyjkowy?",
+      "ovulationTest": "Domowy test moczu wykrywający skok LH — wyrzut hormonu około 24–36 h przed owulacją. Wynik dodatni wskazuje najbardziej płodne okno.",
+      "ovulationTestLabel": "Czym jest test owulacyjny?",
+      "spotting": "Lekkie krwawienie poza okresem.",
+      "spottingLabel": "Czym jest plamienie między okresami?",
+      "pregnancyTest": "Wynik domowego testu ciążowego (hCG).",
+      "pregnancyTestLabel": "Czym jest test ciążowy?",
+      "progesteroneTest": "Test potwierdzający, że doszło do owulacji — progesteron rośnie po niej.",
+      "progesteroneTestLabel": "Czym jest test progesteronu?",
+      "intercourse": "Czy tego dnia doszło do stosunku.",
+      "intercourseLabel": "Co śledzi stosunek?",
+      "protected": "Czy podczas stosunku zastosowano antykoncepcję.",
+      "protectedLabel": "Co oznacza zabezpieczony?"
     }
   },
   "cycleReminders": {

src/components/cycle/field-info.tsx

@@ -0,0 +1,61 @@
+"use client";
+
+import { Info } from "lucide-react";
+
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { cn } from "@/lib/utils";
+
+/**
+ * v1.18.1 — the cycle log-sheet field-explainer affordance.
+ *
+ * A small "?" / info icon that puts a factual, descriptive-only one-liner
+ * (what a clinical field means — BBT, cervical mucus, an LH surge) right at
+ * the point of capture, so a first-time user never has to leave the sheet to
+ * understand a term. Mirrors the mood surface's `MoodExplainerIcon` precedent
+ * (self-contained `TooltipProvider`, a real focusable `<button>` trigger with
+ * an `aria-label`, keyboard- and SR-reachable via Radix) but bumps the hit
+ * area to ≥44 px for touch, since the cycle sheet is a thumb-first surface.
+ *
+ * Copy stays descriptive-only — never diagnosis or medical advice — matching
+ * the phase-education honesty gate.
+ */
+export function FieldInfo({
+  label,
+  detail,
+  className,
+}: {
+  /** Accessible name for the trigger (what the icon explains). */
+  label: string;
+  /** The explanation shown in the tooltip. */
+  detail: string;
+  className?: string;
+}) {
+  return (
+    <TooltipProvider delayDuration={150}>
+      <Tooltip>
+        <TooltipTrigger
+          type="button"
+          aria-label={label}
+          data-slot="cycle-field-info"
+          className={cn(
+            // size-6 icon inside an 11-unit (44 px) hit box so touch targets
+            // clear the WCAG 2.5.8 / Apple HIG minimum without enlarging the
+            // visible glyph.
+            "text-muted-foreground hover:text-foreground focus-visible:ring-ring -m-2.5 inline-flex size-11 shrink-0 items-center justify-center rounded-full p-2.5 transition-colors focus-visible:ring-2 focus-visible:outline-none",
+            className,
+          )}
+        >
+          <Info className="size-4" aria-hidden="true" />
+        </TooltipTrigger>
+        <TooltipContent className="max-w-[16rem] text-xs leading-snug">
+          {detail}
+        </TooltipContent>
+      </Tooltip>
+    </TooltipProvider>
+  );
+}