fix(web): disable anonymous login by default (guest button removal)

claudemesh requires an account — mesh membership is tied to user.id.
e8ad7a5 flipped the config default but the env var override at
env.config.ts:43 still defaulted to true, keeping the button visible.

Fixed at env var level + example files. Needs Coolify rebuild since
NEXT_PUBLIC_* is build-time in Next standalone.

.env.production.example

@@ -51,7 +51,7 @@ NEXT_PUBLIC_THEME_COLOR="orange"
 NEXT_PUBLIC_AUTH_PASSWORD=true
 NEXT_PUBLIC_AUTH_MAGIC_LINK=false
 NEXT_PUBLIC_AUTH_PASSKEY=true
-NEXT_PUBLIC_AUTH_ANONYMOUS=true
+NEXT_PUBLIC_AUTH_ANONYMOUS=false
 
 # [OPTIONAL] Signup credits (default: 100 in production)
 FREE_TIER_CREDITS=100