refactor: rename mascot to chatbot across entire codebase

- Backend: mascot-chat module → chatbot, routes /mascot/chat → /chat
- Shared schema: pgMascotChatMessagesTable → pgChatbotMessagesTable
- Frontend: MascotProvider/useMascot → ChatbotProvider/useChatbot
- Gateway schema: update exports to match shared schema
- Docs: update all .md references (CLAUDE.md, README, specs, plans)
- All API routes, controller names, service classes, types renamed

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

services/backend/src/modules/chatbot/chatbot.controller.ts

@@ -0,0 +1,84 @@
+import { createChildLogger } from "@bete/shared/logger";
+import type { Request, Response } from "express";
+import { asyncHandler } from "../../shared/middlewares/index.js";
+import { chatbotService } from "./chatbot.service.js";
+
+const logger = createChildLogger("chatbot.controller");
+
+interface AuthenticatedRequest extends Request {
+  userId?: string;
+}
+
+export const handleChatbotChat = asyncHandler(
+  async (req: Request, res: Response) => {
+    const { message, context } = req.body as {
+      message: string;
+      context?: Record<string, unknown>;
+    };
+
+    // Validate required fields
+    if (!message || typeof message !== "string") {
+      return res.status(400).json({
+        error: "INVALID_INPUT",
+        message: "Message is required and must be a string",
+      });
+    }
+
+    // Get user ID from auth middleware (if available)
+    const userId = (req as AuthenticatedRequest).userId || "anonymous";
+
+    logger.debug(
+      { userId, messageLength: message.length, context },
+      "Received chatbot chat message",
+    );
+
+    // Process message & generate response
+    const response = await chatbotService.processMessage(
+      message,
+      context,
+      userId,
+    );
+
+    // Save conversation to database
+    await chatbotService.saveConversation({
+      userId,
+      userMessage: message,
+      botResponse: response,
+      context,
+      timestamp: new Date(),
+    });
+
+    logger.info({ userId }, "Chatbot chat processed successfully");
+
+    res.status(200).json({
+      response,
+      timestamp: new Date().toISOString(),
+    });
+  },
+);
+
+export const getChatbotHistory = asyncHandler(
+  async (req: Request, res: Response) => {
+    const userId = (req as AuthenticatedRequest).userId || "anonymous";
+    const limit = Math.min(parseInt(req.query.limit as string, 10) || 50, 100);
+
+    const history = await chatbotService.getChatHistory(userId, limit);
+
+    res.status(200).json({
+      history,
+      total: history.length,
+    });
+  },
+);
+
+export const clearChatbotHistory = asyncHandler(
+  async (req: Request, res: Response) => {
+    const userId = (req as AuthenticatedRequest).userId || "anonymous";
+
+    await chatbotService.clearChatHistory(userId);
+
+    res.status(200).json({
+      message: "Chat history cleared successfully",
+    });
+  },
+);