fix(discord): restore voice UDP routing on Cloudflare Anycast while isolating web traffic

- Preserve raw Cloudflare subnets in community-subnets-discord.lst in updates.uc instead of destructive deletion.
- In singbox/generator_routes.uc:
  * Exclude Cloudflare Anycast CIDRs from general IP route rules (preventing web hijacking).
  * Generate a dedicated Discord Voice route rule for Cloudflare subnets scoped to network: 'udp' and voice port ranges (50000-65535, 3478, 19302, 5000-5020).
  * Provide DEFAULT_DISCORD_VOICE_SUBNETS fallback in core/ip.uc.
- In nft/apply.uc:
  * Route Cloudflare subnets to ip_ports set with Discord voice ports (5000-5020, 3478, 19302, 50000-65535).
  * Automatically enable ip_port rules when section has community_subnets for Discord.
- In section.js (Routing Rule Tracer):
  * Filter out Cloudflare subnets when resolving domain web traffic to Discord community subnets.
  * Accurately display voice UDP routing notice for Anycast ranges.
- Update tests/community_subnets_sanitization.sh with voice UDP and sing-box validation.

tachyon/files/usr/lib/components/updates.uc

@@ -2519,15 +2519,11 @@ function import_all_preset_lists(settings) {
                 }
             }
 
-            let core_ip = core_ip_module_or_null();
             let lines = split(as_string(fs.readfile(tmpfile)), "\n");
             for (let l in lines) {
                 l = trim(replace(as_string(l), /\r/g, ""));
-                if (l != "" && substr(l, 0, 1) != "#") {
-                    if (as_string(service) == "discord" && core_ip && core_ip.is_cloudflare_shared_cidr(l))
-                        continue;
+                if (l != "" && substr(l, 0, 1) != "#")
                     push(combined_lines, l);
-                }
             }
 
             if (downloaded)
@@ -2589,20 +2585,12 @@ function import_builtin_subnets_from_rule(section, settings) {
                 }
             }
 
-            let core_ip = core_ip_module_or_null();
             let lines = split(as_string(fs.readfile(tmpfile)), "\n");
-            let filtered_for_nft = [];
             for (let l in lines) {
                 l = trim(replace(as_string(l), /\r/g, ""));
-                if (l != "" && substr(l, 0, 1) != "#") {
-                    if (as_string(service) == "discord" && core_ip && core_ip.is_cloudflare_shared_cidr(l))
-                        continue;
+                if (l != "" && substr(l, 0, 1) != "#")
                     push(combined_lines, l);
-                    push(filtered_for_nft, l);
-                }
             }
-            if (as_string(service) == "discord")
-                write_file(tmpfile, join("\n", filtered_for_nft) + "\n");
 
             nft_module_success([
                 "nft-add-community-subnet-file-for-uci-section",