fix(migrations): baseline existing tables + add 0003 for missing suggestions table

- entrypoint.sh: resolve --applied 0000 and 0001 before deploying,
  so prisma skips them and only runs 0002 (message_logs) and 0003 (suggestions)
- migration 0003: CREATE TABLE IF NOT EXISTS suggestions

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

backend/prisma/migrations/0003_add_suggestions/migration.sql

@@ -0,0 +1,9 @@
+-- CreateTable
+CREATE TABLE IF NOT EXISTS "suggestions" (
+    "id" UUID NOT NULL DEFAULT uuid_generate_v4(),
+    "name" VARCHAR(255),
+    "message" TEXT NOT NULL,
+    "created_at" TIMESTAMPTZ(6) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "suggestions_pkey" PRIMARY KEY ("id")
+);