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/config/configuration.ts

@@ -40,6 +40,12 @@ export default () => ({
     username: process.env.EMEX_USERNAME,
     password: process.env.EMEX_PASSWORD,
   },
+  email: {
+    postalApiUrl: process.env.POSTAL_API_URL,
+    postalApiKey: process.env.POSTAL_API_KEY,
+    fromAddress: process.env.POSTAL_FROM_ADDRESS || "noreply@sase.tr",
+    fromName: process.env.POSTAL_FROM_NAME || "Sase.tr",
+  },
   otel: {
     enabled: process.env.OTEL_ENABLED === "true",
     endpoint: process.env.OTEL_EXPORTER_OTLP_ENDPOINT,