feat: initialize prisma with Stock model

prisma/migrations/20260514075455_init/migration.sql

@@ -0,0 +1,11 @@
+-- CreateTable
+CREATE TABLE "Stock" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "ticker" TEXT NOT NULL,
+    "notes" TEXT,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "Stock_ticker_key" ON "Stock"("ticker");