feat(db): encrypt Profile health fields at rest (ADR 0002)

Wire prisma-field-encryption AES-256-GCM extension on the shared Prisma
client and annotate the four sensitive columns on Profile with @encrypted:
- weightStartKg / weightCurrentKg / weightGoalKg (Decimal → String)
- targetDate (DateTime @db.Date → String, ISO YYYY-MM-DD)

Other Profile fields stay in clear text per ADR 0002 (age, gender,
heightCm, activityLevel) — they're needed for plan generation and
aggregate analytics, and are not strongly identifying on their own.

apps/api profile.routes.ts:
- serialize() now reads the columns as strings and parses them back to
  numbers for BMR/TDEE; targetDate is already an ISO string from the DB
- the upsert stringifies numeric inputs and slices the date to YYYY-MM-DD

Env wiring:
- packages/db, apps/api, apps/web .env.example all document
  PRISMA_FIELD_ENCRYPTION_KEY (k1.aesgcm256.<base64url>) — must match
  across every process that hits the DB
- key generation snippet documented inline

Migration is intentionally NOT in this commit: needs to be created against
a live Postgres instance and applied. The fields change Decimal/Date → text
so prisma migrate dev will require a USING cast — see the follow-up commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/.env.example

@@ -8,6 +8,11 @@ CORS_ORIGINS=http://localhost:3000
 
 DATABASE_URL=postgresql://luciano:luciano%40@localhost:5432/ketopath?schema=public
 
+# Cifratura at-rest dei campi sanitari (vedi ADR 0002).
+# Genera con: node -e "console.log('k1.aesgcm256.'+require('crypto').generateKeySync('aes',{length:256}).export().toString('base64url'))"
+# DEVE coincidere con apps/web/.env e con tutti i deploy che leggono il DB.
+PRISMA_FIELD_ENCRYPTION_KEY=
+
 # Better Auth — DEVE coincidere con apps/web/.env (sessione condivisa)
 BETTER_AUTH_SECRET=
 BETTER_AUTH_URL=http://localhost:3000

apps/api/src/modules/profile/profile.routes.ts

@@ -10,21 +10,24 @@ import type { FastifyPluginAsync } from 'fastify';
 
 import { requireAuth } from '../../plugins/auth.js';
 
+// The weight columns are encrypted at rest (ADR 0002) and therefore stored
+// as String. The Zod input schema parses numeric strings → numbers, but the
+// Prisma row keeps them as strings — so serialize/parse explicitly here.
 function serialize(
   profile: {
     age: number;
     gender: Gender;
     heightCm: number;
-    weightStartKg: { toNumber(): number };
-    weightCurrentKg: { toNumber(): number };
-    weightGoalKg: { toNumber(): number };
+    weightStartKg: string;
+    weightCurrentKg: string;
+    weightGoalKg: string;
     activityLevel: ActivityLevel;
-    targetDate: Date | null;
+    targetDate: string | null;
     currentPhase: string;
   } | null,
 ) {
   if (!profile) return null;
-  const weightCurrentKg = profile.weightCurrentKg.toNumber();
+  const weightCurrentKg = Number(profile.weightCurrentKg);
   const bmr = calculateBmr({
     weightKg: weightCurrentKg,
     heightCm: profile.heightCm,
@@ -36,11 +39,11 @@ function serialize(
     age: profile.age,
     gender: profile.gender,
     heightCm: profile.heightCm,
-    weightStartKg: profile.weightStartKg.toNumber(),
+    weightStartKg: Number(profile.weightStartKg),
     weightCurrentKg,
-    weightGoalKg: profile.weightGoalKg.toNumber(),
+    weightGoalKg: Number(profile.weightGoalKg),
     activityLevel: profile.activityLevel,
-    targetDate: profile.targetDate?.toISOString() ?? null,
+    targetDate: profile.targetDate,
     currentPhase: profile.currentPhase,
     derived: {
       bmr: Math.round(bmr),
@@ -67,6 +70,8 @@ export const profileRoutes: FastifyPluginAsync = async (fastify) => {
     const data = parsed.data;
     const userId = request.user!.id;
 
+    const targetDateStr = data.targetDate ? data.targetDate.toISOString().slice(0, 10) : null;
+
     const profile = await fastify.prisma.profile.upsert({
       where: { userId },
       create: {
@@ -74,21 +79,21 @@ export const profileRoutes: FastifyPluginAsync = async (fastify) => {
         age: data.age,
         gender: data.gender,
         heightCm: data.heightCm,
-        weightStartKg: data.weightStartKg,
-        weightCurrentKg: data.weightCurrentKg,
-        weightGoalKg: data.weightGoalKg,
+        weightStartKg: String(data.weightStartKg),
+        weightCurrentKg: String(data.weightCurrentKg),
+        weightGoalKg: String(data.weightGoalKg),
         activityLevel: data.activityLevel,
-        targetDate: data.targetDate ?? null,
+        targetDate: targetDateStr,
       },
       update: {
         age: data.age,
         gender: data.gender,
         heightCm: data.heightCm,
-        weightStartKg: data.weightStartKg,
-        weightCurrentKg: data.weightCurrentKg,
-        weightGoalKg: data.weightGoalKg,
+        weightStartKg: String(data.weightStartKg),
+        weightCurrentKg: String(data.weightCurrentKg),
+        weightGoalKg: String(data.weightGoalKg),
         activityLevel: data.activityLevel,
-        targetDate: data.targetDate ?? null,
+        targetDate: targetDateStr,
       },
     });
 

apps/web/.env.example

@@ -12,6 +12,10 @@ BETTER_AUTH_URL=http://localhost:3000
 # Database (Better Auth usa @ketopath/db, che legge DATABASE_URL)
 DATABASE_URL=postgresql://luciano:luciano%40@localhost:5432/ketopath?schema=public
 
+# Cifratura at-rest dei campi sanitari (vedi ADR 0002).
+# DEVE essere identica a apps/api/.env.
+PRISMA_FIELD_ENCRYPTION_KEY=
+
 # Google OAuth (configurato a fine progetto)
 # GOOGLE_CLIENT_ID=
 # GOOGLE_CLIENT_SECRET=

packages/db/.env.example

@@ -1 +1,4 @@
 DATABASE_URL="postgresql://luciano:luciano%40@localhost:5432/ketopath?schema=public"
+
+# Cifratura at-rest (vedi ADR 0002). Stesso valore in apps/api/.env e apps/web/.env.
+PRISMA_FIELD_ENCRYPTION_KEY=

packages/db/package.json

@@ -19,7 +19,8 @@
     "db:seed": "tsx prisma/seed.ts"
   },
   "dependencies": {
-    "@prisma/client": "^5.18.0"
+    "@prisma/client": "^5.18.0",
+    "prisma-field-encryption": "^1.6.0"
   },
   "devDependencies": {
     "@ketopath/eslint-config": "workspace:*",

packages/db/prisma/schema.prisma

@@ -128,11 +128,15 @@ model Profile {
   age             Int
   gender          Gender
   heightCm        Int           @map("height_cm")
-  weightStartKg   Decimal       @map("weight_start_kg") @db.Decimal(5, 2)
-  weightCurrentKg Decimal       @map("weight_current_kg") @db.Decimal(5, 2)
-  weightGoalKg    Decimal       @map("weight_goal_kg") @db.Decimal(5, 2)
+  /// @encrypted
+  weightStartKg   String        @map("weight_start_kg")
+  /// @encrypted
+  weightCurrentKg String        @map("weight_current_kg")
+  /// @encrypted
+  weightGoalKg    String        @map("weight_goal_kg")
   activityLevel   ActivityLevel @map("activity_level")
-  targetDate      DateTime?     @map("target_date") @db.Date
+  /// @encrypted
+  targetDate      String?       @map("target_date")
   currentPhase    Phase         @default(INTENSIVE) @map("current_phase")
   createdAt       DateTime      @default(now()) @map("created_at")
   updatedAt       DateTime      @updatedAt @map("updated_at")

packages/db/src/client.ts

@@ -1,13 +1,19 @@
 import { PrismaClient } from '@prisma/client';
+import { fieldEncryptionExtension } from 'prisma-field-encryption';
 
+// Singleton-friendly storage of the BASE client (so HMR doesn't open a new pool
+// every time). The exported `prisma` is the EXTENDED client returned by
+// $extends — it wraps the base client with the field-encryption middleware.
 const globalForPrisma = globalThis as unknown as { prisma?: PrismaClient };
 
-export const prisma: PrismaClient =
+const baseClient =
   globalForPrisma.prisma ??
   new PrismaClient({
     log: process.env.NODE_ENV === 'development' ? ['warn', 'error'] : ['error'],
   });
 
 if (process.env.NODE_ENV !== 'production') {
-  globalForPrisma.prisma = prisma;
+  globalForPrisma.prisma = baseClient;
 }
+
+export const prisma = baseClient.$extends(fieldEncryptionExtension());