feat(settings): add Block tab for JSON subscription routing rules (#6466)

* feat(settings): add Block tab for JSON subscription routing rules

Expose the existing blackhole outbound in the subscription formats UI so
operators can add block domain/IP rules without editing subJsonRules by
hand. Scope Direct/Block helpers by outboundTag so the tabs keep separate
rule objects, and keep block rules ahead of direct for Xray match order.

* fix(settings): preserve rule order and clear foreign leftovers

Stop sorting the whole subJsonRules array on every write. Prepend block
defaults only when enabling Block. Clearing the last managed tag also
drops foreign-tag leftovers so the panel can reach an empty setting.
Fixes oxfmt on SubscriptionFormatsTab.

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Co-authored-by: mrchatam <287639636+mrchatam@users.noreply.github.com>

internal/web/translation/en-US.json

@@ -1415,6 +1415,8 @@
       "muxSett": "Mux Settings",
       "direct": "Direct Connection",
       "directDesc": "Directly establishes connections with domains or IP ranges of a specific country.",
+      "block": "Block Connection",
+      "blockDesc": "Block connections to selected domains or IP ranges using the blackhole outbound.",
       "notifications": "Notifications",
       "certs": "Certificates",
       "externalTraffic": "External Traffic",