feat(odin): conversation-scoped service + routes (replace /history)

Remove single-thread getChatHistory/appendChatMessages/clearChatHistory and the
three /history routes; add listConversations, createConversation, getConversation-
Messages, appendConversationMessages, renameConversation, deleteConversation with
ownership checks and auto-title; wire six /conversations[/:id] routes.

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

src/routes/admin/ai.ts

@@ -1,12 +1,14 @@
 import { FastifyInstance, FastifyRequest, FastifyReply } from "fastify";
 import multipart from "@fastify/multipart";
 import { requirePermission } from "../../middleware/auth";
-import { success, error } from "../../utils/response";
+import { success, error, parseId } from "../../utils/response";
 import { parseBody } from "../../schemas/common";
 import {
   AiChatSchema,
   AiBudgetSchema,
   AiHistoryAppendSchema,
+  AiCreateConversationSchema,
+  AiRenameConversationSchema,
 } from "../../schemas/ai.schema";
 import { logAudit } from "../../services/audit";
 import { config } from "../../config/env";
@@ -18,9 +20,12 @@ import {
   setBudgetUsd,
   chat,
   extractInvoice,
-  getChatHistory,
-  appendChatMessages,
-  clearChatHistory,
+  listConversations,
+  createConversation,
+  getConversationMessages,
+  appendConversationMessages,
+  renameConversation,
+  deleteConversation,
   type ExtractedInvoice,
 } from "../../services/ai.service";
 
@@ -131,35 +136,95 @@ export default async function aiRoutes(app: FastifyInstance): Promise<void> {
     },
   );
 
-  // GET /api/admin/ai/history — this user's stored chat thread
+  // GET /conversations — this user's conversations (stable order)
   app.get(
-    "/history",
+    "/conversations",
     { preHandler: requirePermission("ai.use") },
     async (request: FastifyRequest, reply: FastifyReply) => {
-      const messages = await getChatHistory(request.authData!.userId);
-      return success(reply, { messages });
+      const conversations = await listConversations(request.authData!.userId);
+      return success(reply, { conversations });
     },
   );
 
-  // POST /api/admin/ai/history — append turns to this user's thread
+  // POST /conversations — create
   app.post(
-    "/history",
+    "/conversations",
     { preHandler: requirePermission("ai.use") },
     async (request: FastifyRequest, reply: FastifyReply) => {
+      const body = parseBody(AiCreateConversationSchema, request.body);
+      if ("error" in body) return error(reply, body.error, 400);
+      const conversation = await createConversation(
+        request.authData!.userId,
+        body.data.title,
+      );
+      return success(reply, { conversation });
+    },
+  );
+
+  // GET /conversations/:id/messages
+  app.get(
+    "/conversations/:id/messages",
+    { preHandler: requirePermission("ai.use") },
+    async (request: FastifyRequest, reply: FastifyReply) => {
+      const id = parseId((request.params as { id: string }).id, reply);
+      if (id === null) return;
+      const result = await getConversationMessages(
+        request.authData!.userId,
+        id,
+      );
+      if ("error" in result) return error(reply, result.error, result.status);
+      return success(reply, { messages: result.data });
+    },
+  );
+
+  // POST /conversations/:id/messages — append turns
+  app.post(
+    "/conversations/:id/messages",
+    { preHandler: requirePermission("ai.use") },
+    async (request: FastifyRequest, reply: FastifyReply) => {
+      const id = parseId((request.params as { id: string }).id, reply);
+      if (id === null) return;
       const body = parseBody(AiHistoryAppendSchema, request.body);
       if ("error" in body) return error(reply, body.error, 400);
-      await appendChatMessages(request.authData!.userId, body.data.messages);
-      return success(reply, { ok: true });
+      const result = await appendConversationMessages(
+        request.authData!.userId,
+        id,
+        body.data.messages,
+      );
+      if ("error" in result) return error(reply, result.error, result.status);
+      return success(reply, result.data);
     },
   );
 
-  // DELETE /api/admin/ai/history — clear this user's thread
-  app.delete(
-    "/history",
+  // PATCH /conversations/:id — rename
+  app.patch(
+    "/conversations/:id",
     { preHandler: requirePermission("ai.use") },
     async (request: FastifyRequest, reply: FastifyReply) => {
-      await clearChatHistory(request.authData!.userId);
-      return success(reply, { ok: true });
+      const id = parseId((request.params as { id: string }).id, reply);
+      if (id === null) return;
+      const body = parseBody(AiRenameConversationSchema, request.body);
+      if ("error" in body) return error(reply, body.error, 400);
+      const result = await renameConversation(
+        request.authData!.userId,
+        id,
+        body.data.title,
+      );
+      if ("error" in result) return error(reply, result.error, result.status);
+      return success(reply, { conversation: result.data });
+    },
+  );
+
+  // DELETE /conversations/:id
+  app.delete(
+    "/conversations/:id",
+    { preHandler: requirePermission("ai.use") },
+    async (request: FastifyRequest, reply: FastifyReply) => {
+      const id = parseId((request.params as { id: string }).id, reply);
+      if (id === null) return;
+      const result = await deleteConversation(request.authData!.userId, id);
+      if ("error" in result) return error(reply, result.error, result.status);
+      return success(reply, result.data);
     },
   );
 }