fix(ci): migrations idempotentes et deploy prod sans toucher Postgres

Les migrations échouaient sur une base vide (contraintes/index déjà créés par init).
Le workflow deploy ne recrée plus Postgres ni ne force les entrées _prisma_migrations.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/prisma/migrations/20260510123000_add_notebook_hierarchy_and_trash/migration.sql

@@ -1,18 +1,32 @@
--- AlterTable
-ALTER TABLE "Label" ADD COLUMN "type" TEXT NOT NULL DEFAULT 'user';
+-- AlterTable Label (may already exist from 20260509160000_add_missing_columns)
+DO $$ BEGIN
+  ALTER TABLE "Label" ADD COLUMN "type" TEXT NOT NULL DEFAULT 'user';
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;
 
--- AlterTable
-ALTER TABLE "UserAISettings" ADD COLUMN "autoSave" BOOLEAN NOT NULL DEFAULT true;
+-- AlterTable UserAISettings
+DO $$ BEGIN
+  ALTER TABLE "UserAISettings" ADD COLUMN "autoSave" BOOLEAN NOT NULL DEFAULT true;
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;
 
--- AlterTable
-ALTER TABLE "Notebook" ADD COLUMN "parentId" TEXT,
-ADD COLUMN "trashedAt" TIMESTAMP(3);
+-- AlterTable Notebook
+DO $$ BEGIN
+  ALTER TABLE "Notebook" ADD COLUMN "parentId" TEXT;
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;
 
--- CreateIndex
-CREATE INDEX "Notebook_parentId_idx" ON "Notebook"("parentId");
+DO $$ BEGIN
+  ALTER TABLE "Notebook" ADD COLUMN "trashedAt" TIMESTAMP(3);
+EXCEPTION WHEN duplicate_column THEN NULL;
+END $$;
 
--- CreateIndex
-CREATE INDEX "Notebook_trashedAt_idx" ON "Notebook"("trashedAt");
+CREATE INDEX IF NOT EXISTS "Notebook_parentId_idx" ON "Notebook"("parentId");
+CREATE INDEX IF NOT EXISTS "Notebook_trashedAt_idx" ON "Notebook"("trashedAt");
 
--- AddForeignKey
-ALTER TABLE "Notebook" ADD CONSTRAINT "Notebook_parentId_fkey" FOREIGN KEY ("parentId") REFERENCES "Notebook"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+DO $$ BEGIN
+  ALTER TABLE "Notebook" ADD CONSTRAINT "Notebook_parentId_fkey" FOREIGN KEY ("parentId") REFERENCES "Notebook"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+EXCEPTION
+  WHEN duplicate_object THEN NULL;
+  WHEN duplicate_table THEN NULL;
+END $$;