feat(sub): auto-detect subscription format by User-Agent (Updated) (#5826)

* feat(settings): add subscription format controls

* feat(sub): auto-detect subscription formats

* fix(xray): validate balancer regexes before save

* Revert "fix(xray): validate balancer regexes before save"

This reverts commit 8a208ce71b.

* doc(endpoints): align indent spaces

* doc(settings): improve error message formatting in validateSubUserAgentRegex

- Use NewErrorf with proper formatting instead of NewError with string concatenation
- Add comment explaining the rationale for returning original pattern value
- This preserves the intentional design where empty input is stored as empty
  in the DB and inherited as the runtime default at read time

---------

Co-authored-by: Tomilla <5007859+Tomilla@users.noreply.github.com>
Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>

frontend/src/generated/examples.ts

@@ -45,11 +45,13 @@ export const EXAMPLES: Record<string, unknown> = {
     "smtpUsername": "",
     "subAnnounce": "",
     "subCertFile": "",
+    "subClashAutoDetect": false,
     "subClashEnable": false,
     "subClashEnableRouting": false,
     "subClashPath": "",
     "subClashRules": "",
     "subClashURI": "",
+    "subClashUserAgentRegex": "",
     "subDomain": "",
     "subEnable": false,
     "subEnableRouting": false,
@@ -57,12 +59,15 @@ export const EXAMPLES: Record<string, unknown> = {
     "subHideSettings": false,
     "subIncyEnableRouting": false,
     "subIncyRoutingRules": "",
+    "subJsonAlwaysArray": false,
+    "subJsonAutoDetect": false,
     "subJsonEnable": false,
     "subJsonFinalMask": "",
     "subJsonMux": "",
     "subJsonPath": "",
     "subJsonRules": "",
     "subJsonURI": "",
+    "subJsonUserAgentRegex": "",
     "subKeyFile": "",
     "subListen": "",
     "subPath": "",
@@ -150,11 +155,13 @@ export const EXAMPLES: Record<string, unknown> = {
     "smtpUsername": "",
     "subAnnounce": "",
     "subCertFile": "",
+    "subClashAutoDetect": false,
     "subClashEnable": false,
     "subClashEnableRouting": false,
     "subClashPath": "",
     "subClashRules": "",
     "subClashURI": "",
+    "subClashUserAgentRegex": "",
     "subDomain": "",
     "subEnable": false,
     "subEnableRouting": false,
@@ -162,12 +169,15 @@ export const EXAMPLES: Record<string, unknown> = {
     "subHideSettings": false,
     "subIncyEnableRouting": false,
     "subIncyRoutingRules": "",
+    "subJsonAlwaysArray": false,
+    "subJsonAutoDetect": false,
     "subJsonEnable": false,
     "subJsonFinalMask": "",
     "subJsonMux": "",
     "subJsonPath": "",
     "subJsonRules": "",
     "subJsonURI": "",
+    "subJsonUserAgentRegex": "",
     "subKeyFile": "",
     "subListen": "",
     "subPath": "",