feat(21-01): add chat_conversations and chat_messages Drizzle schema + migration

- Create chatConversations table with companyId FK, agentId FK (set null), pinned/archived/deleted timestamps
- Create chatMessages table with conversationId FK (cascade delete), role, content, agentId
- Export both tables from packages/db/src/schema/index.ts
- Generate migration 0047_nebulous_klaw.sql with full DDL, FK constraints, and indexes

packages/db/src/migrations/0047_nebulous_klaw.sql

@@ -0,0 +1,27 @@
+CREATE TABLE "chat_conversations" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"company_id" uuid NOT NULL,
+	"title" text,
+	"agent_id" uuid,
+	"pinned_at" timestamp with time zone,
+	"archived_at" timestamp with time zone,
+	"deleted_at" timestamp with time zone,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE "chat_messages" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"conversation_id" uuid NOT NULL,
+	"role" text NOT NULL,
+	"content" text NOT NULL,
+	"agent_id" uuid,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE "chat_conversations" ADD CONSTRAINT "chat_conversations_company_id_companies_id_fk" FOREIGN KEY ("company_id") REFERENCES "public"."companies"("id") ON DELETE no action ON UPDATE no action;--> statement-breakpoint
+ALTER TABLE "chat_conversations" ADD CONSTRAINT "chat_conversations_agent_id_agents_id_fk" FOREIGN KEY ("agent_id") REFERENCES "public"."agents"("id") ON DELETE set null ON UPDATE no action;--> statement-breakpoint
+ALTER TABLE "chat_messages" ADD CONSTRAINT "chat_messages_conversation_id_chat_conversations_id_fk" FOREIGN KEY ("conversation_id") REFERENCES "public"."chat_conversations"("id") ON DELETE cascade ON UPDATE no action;--> statement-breakpoint
+CREATE INDEX "chat_conversations_company_updated_idx" ON "chat_conversations" USING btree ("company_id","updated_at");--> statement-breakpoint
+CREATE INDEX "chat_conversations_company_deleted_idx" ON "chat_conversations" USING btree ("company_id","deleted_at");--> statement-breakpoint
+CREATE INDEX "chat_messages_conversation_created_idx" ON "chat_messages" USING btree ("conversation_id","created_at");

packages/db/src/schema/chat_conversations.ts

@@ -0,0 +1,22 @@
+import { pgTable, uuid, text, timestamp, index } from "drizzle-orm/pg-core";
+import { companies } from "./companies.js";
+import { agents } from "./agents.js";
+
+export const chatConversations = pgTable(
+  "chat_conversations",
+  {
+    id: uuid("id").primaryKey().defaultRandom(),
+    companyId: uuid("company_id").notNull().references(() => companies.id),
+    title: text("title"),
+    agentId: uuid("agent_id").references(() => agents.id, { onDelete: "set null" }),
+    pinnedAt: timestamp("pinned_at", { withTimezone: true }),
+    archivedAt: timestamp("archived_at", { withTimezone: true }),
+    deletedAt: timestamp("deleted_at", { withTimezone: true }),
+    createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
+    updatedAt: timestamp("updated_at", { withTimezone: true }).notNull().defaultNow(),
+  },
+  (table) => ({
+    companyUpdatedIdx: index("chat_conversations_company_updated_idx").on(table.companyId, table.updatedAt),
+    companyDeletedIdx: index("chat_conversations_company_deleted_idx").on(table.companyId, table.deletedAt),
+  }),
+);

packages/db/src/schema/chat_messages.ts

@@ -0,0 +1,18 @@
+import { pgTable, uuid, text, timestamp, index } from "drizzle-orm/pg-core";
+import { chatConversations } from "./chat_conversations.js";
+
+export const chatMessages = pgTable(
+  "chat_messages",
+  {
+    id: uuid("id").primaryKey().defaultRandom(),
+    conversationId: uuid("conversation_id").notNull()
+      .references(() => chatConversations.id, { onDelete: "cascade" }),
+    role: text("role").notNull(),
+    content: text("content").notNull(),
+    agentId: uuid("agent_id"),
+    createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
+  },
+  (table) => ({
+    conversationCreatedIdx: index("chat_messages_conversation_created_idx").on(table.conversationId, table.createdAt),
+  }),
+);

packages/db/src/schema/index.ts

@@ -58,3 +58,5 @@ export { pluginEntities } from "./plugin_entities.js";
 export { pluginJobs, pluginJobRuns } from "./plugin_jobs.js";
 export { pluginWebhookDeliveries } from "./plugin_webhooks.js";
 export { pluginLogs } from "./plugin_logs.js";
+export { chatConversations } from "./chat_conversations.js";
+export { chatMessages } from "./chat_messages.js";