Corrige l'échec du build Docker : initialisation paresseuse du client DB

`next build` collecte les données de page en important les modules serveur sans
DATABASE_URL ; l'ancien client jetait une erreur dès l'import. Le client Drizzle
est désormais initialisé paresseusement (via un Proxy) à la première requête,
donc l'import est sans effet de bord et le build n'exige plus DATABASE_URL.
Vérifié : build OK sans variables d'env, et requêtes runtime OK via le proxy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XwfhYHzC9hQWPDnQ2p53GL

src/db/index.ts

@@ -1,25 +1,48 @@
-import { drizzle } from "drizzle-orm/node-postgres";
+import { drizzle, type NodePgDatabase } from "drizzle-orm/node-postgres";
 import { Pool } from "pg";
 import * as schema from "./schema";
 
-const connectionString = process.env.DATABASE_URL;
-if (!connectionString) {
-  throw new Error("DATABASE_URL is not set");
-}
+// Lazily initialise the pool + drizzle client so that merely *importing* this
+// module never requires DATABASE_URL. This matters during `next build`, which
+// collects page data by importing server modules without runtime env set.
+const globalForDb = globalThis as unknown as {
+  __pleinrPool?: Pool;
+  __pleinrDb?: NodePgDatabase<typeof schema>;
+};
 
-// Reuse the pool across hot reloads in dev to avoid exhausting connections.
-const globalForDb = globalThis as unknown as { __pleinrPool?: Pool };
-
-export const pool =
-  globalForDb.__pleinrPool ??
-  new Pool({
+function getPool(): Pool {
+  if (globalForDb.__pleinrPool) return globalForDb.__pleinrPool;
+  const connectionString = process.env.DATABASE_URL;
+  if (!connectionString) {
+    throw new Error("DATABASE_URL is not set");
+  }
+  const pool = new Pool({
     connectionString,
     max: Number(process.env.PG_POOL_MAX ?? 10),
   });
-
-if (process.env.NODE_ENV !== "production") {
   globalForDb.__pleinrPool = pool;
+  return pool;
+}
+
+function getDb(): NodePgDatabase<typeof schema> {
+  if (globalForDb.__pleinrDb) return globalForDb.__pleinrDb;
+  const instance = drizzle(getPool(), { schema });
+  globalForDb.__pleinrDb = instance;
+  return instance;
+}
+
+// Proxy that defers initialisation until the first property access (i.e. the
+// first query at request time), so imports stay side-effect free.
+export const db = new Proxy({} as NodePgDatabase<typeof schema>, {
+  get(_target, prop, receiver) {
+    const instance = getDb();
+    const value = Reflect.get(instance as object, prop, receiver);
+    return typeof value === "function" ? value.bind(instance) : value;
+  },
+});
+
+export function getPgPool(): Pool {
+  return getPool();
 }
 
-export const db = drizzle(pool, { schema });
 export { schema };