feat: add OEM code copy tracking, PostHog analytics, Postal email integration

- Add oem_code_copies table and analytics module for tracking part code copies
- Integrate PostHog for frontend product analytics (VIN decode, OEM copy events)
- Switch email service from stub to Postal API with proper error handling
- Add copy button to parts panel with clipboard + server-side logging
- Add admin copy-logs page with filtering and top-copied-codes view
- Add VIN report endpoint for users to flag unrecognized chassis numbers
- Add Postal email env vars to config schema

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

apps/api/src/analytics/analytics.controller.ts

@@ -0,0 +1,29 @@
+import { Body, Controller, Post } from "@nestjs/common";
+import { AnalyticsService } from "./analytics.service";
+import { CurrentUser } from "../common/decorators/current-user.decorator";
+
+@Controller("analytics")
+export class AnalyticsController {
+  constructor(private analyticsService: AnalyticsService) {}
+
+  @Post("oem-copy")
+  async trackOemCopy(
+    @CurrentUser() user: { id: string },
+    @Body()
+    body: {
+      oemCode: string;
+      partId?: string;
+      vehicleId?: string;
+      categoryId?: string;
+    },
+  ) {
+    await this.analyticsService.trackOemCodeCopy({
+      userId: user.id,
+      oemCode: body.oemCode,
+      partId: body.partId,
+      vehicleId: body.vehicleId,
+      categoryId: body.categoryId,
+    });
+    return { tracked: true };
+  }
+}

apps/api/src/analytics/analytics.module.ts

@@ -0,0 +1,10 @@
+import { Module } from "@nestjs/common";
+import { AnalyticsController } from "./analytics.controller";
+import { AnalyticsService } from "./analytics.service";
+
+@Module({
+  controllers: [AnalyticsController],
+  providers: [AnalyticsService],
+  exports: [AnalyticsService],
+})
+export class AnalyticsModule {}

apps/api/src/analytics/analytics.service.ts

@@ -0,0 +1,85 @@
+import { Inject, Injectable, Logger } from "@nestjs/common";
+import { count, desc, eq, gte, sql } from "drizzle-orm";
+import { DATABASE, Database } from "../database/database.provider";
+import { oemCodeCopies, users } from "../database/schema/core";
+
+@Injectable()
+export class AnalyticsService {
+  private readonly logger = new Logger(AnalyticsService.name);
+
+  constructor(@Inject(DATABASE) private db: Database) {}
+
+  async trackOemCodeCopy(data: {
+    userId: string;
+    oemCode: string;
+    partId?: string;
+    vehicleId?: string;
+    categoryId?: string;
+  }) {
+    try {
+      await this.db.insert(oemCodeCopies).values({
+        userId: data.userId,
+        oemCode: data.oemCode,
+        partId: data.partId ?? null,
+        vehicleId: data.vehicleId ?? null,
+        categoryId: data.categoryId ?? null,
+      });
+    } catch (err) {
+      this.logger.error("Failed to track OEM code copy", (err as Error).stack);
+    }
+  }
+
+  async getCopyLogs(page = 1, limit = 50, userId?: string) {
+    const offset = (page - 1) * limit;
+
+    const conditions = userId ? eq(oemCodeCopies.userId, userId) : undefined;
+
+    const [items, totalResult] = await Promise.all([
+      this.db
+        .select({
+          id: oemCodeCopies.id,
+          userId: oemCodeCopies.userId,
+          userName: users.name,
+          userEmail: users.email,
+          oemCode: oemCodeCopies.oemCode,
+          partId: oemCodeCopies.partId,
+          vehicleId: oemCodeCopies.vehicleId,
+          categoryId: oemCodeCopies.categoryId,
+          createdAt: oemCodeCopies.createdAt,
+        })
+        .from(oemCodeCopies)
+        .innerJoin(users, eq(oemCodeCopies.userId, users.id))
+        .where(conditions)
+        .orderBy(desc(oemCodeCopies.createdAt))
+        .limit(limit)
+        .offset(offset),
+      this.db.select({ count: count() }).from(oemCodeCopies).where(conditions),
+    ]);
+
+    return {
+      items,
+      total: totalResult[0].count,
+      page,
+      limit,
+      totalPages: Math.ceil(totalResult[0].count / limit),
+    };
+  }
+
+  async getTopCopiedCodes(days = 30, limit = 20) {
+    const since = new Date(Date.now() - days * 24 * 60 * 60 * 1000);
+
+    const result = await this.db
+      .select({
+        oemCode: oemCodeCopies.oemCode,
+        copyCount: count().as("copy_count"),
+        uniqueUsers: sql<number>`count(distinct ${oemCodeCopies.userId})`.as("unique_users"),
+      })
+      .from(oemCodeCopies)
+      .where(gte(oemCodeCopies.createdAt, since))
+      .groupBy(oemCodeCopies.oemCode)
+      .orderBy(sql`count(*) desc`)
+      .limit(limit);
+
+    return result;
+  }
+}