Remove auth/db stack, migrate contact email flow, and update for Next 16

.env.example

@@ -9,13 +9,18 @@
 # When adding additional environment variables, the schema in "/src/env.js"
 # should be updated accordingly.
 
-# Better Auth
-# Secret used by Better Auth
-BETTER_AUTH_SECRET=""
+# Contact form email — where submissions get forwarded. Set SMTP_HOST and
+# CONTACT_TO to enable delivery; without them, submissions are only logged.
+SMTP_HOST=""
+SMTP_PORT="587"
+# "true" for port 465 (implicit TLS), "false" for 587 (STARTTLS).
+SMTP_SECURE="false"
+SMTP_USER=""
+SMTP_PASS=""
+# Your inbox (where inquiries land) and the From address they're sent as.
+CONTACT_TO=""
+CONTACT_FROM="Hadlock Technologies <no-reply@hadlock.tech>"
 
-# Better Auth GitHub OAuth
-BETTER_AUTH_GITHUB_CLIENT_ID=""
-BETTER_AUTH_GITHUB_CLIENT_SECRET=""
-
-# Drizzle
-DATABASE_URL="file:./db.sqlite"
+# Umami analytics (optional) — set both to enable the tracking script.
+NEXT_PUBLIC_UMAMI_SRC=""
+NEXT_PUBLIC_UMAMI_WEBSITE_ID=""