feat: prisma schema User + SyncRun + seed admin

Sets up Prisma 7 with SQLite (better-sqlite3 adapter), User and SyncRun models, migration, and admin seed account for mathieu.fort@gmail.com.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

prisma/migrations/20260606142603_init/migration.sql

@@ -0,0 +1,26 @@
+-- CreateTable
+CREATE TABLE "User" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "email" TEXT NOT NULL,
+    "name" TEXT NOT NULL,
+    "password" TEXT NOT NULL,
+    "role" TEXT NOT NULL DEFAULT 'gestionnaire',
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+-- CreateTable
+CREATE TABLE "SyncRun" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "userId" TEXT NOT NULL,
+    "status" TEXT NOT NULL,
+    "created" INTEGER NOT NULL DEFAULT 0,
+    "updated" INTEGER NOT NULL DEFAULT 0,
+    "deactivated" INTEGER NOT NULL DEFAULT 0,
+    "errors" INTEGER NOT NULL DEFAULT 0,
+    "log" TEXT NOT NULL DEFAULT '[]',
+    CONSTRAINT "SyncRun_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User" ("id") ON DELETE RESTRICT ON UPDATE CASCADE
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "User_email_key" ON "User"("email");