fix(xhttp): stop injecting scMaxEachPostBytes/scMinPostsIntervalMs defaults (#5141)

The panel seeded xhttp configs with scMaxEachPostBytes=1000000 and
scMinPostsIntervalMs=30 — xray-core''s own defaults — and emitted them
into every generated config and share link. The literal
scMinPostsIntervalMs=30 is a stable DPI fingerprint that Russia''s TSPU
keys on to block connections on mobile networks.

New configs no longer seed these values (empty schema/template defaults,
so xray-core applies its internal defaults). For configs already stored
with the old defaults, the link/subscription builders now drop values
equal to xray-core''s defaults instead of advertising them — covering
panel share links, the raw subscription, and the JSON subscription
without requiring every inbound to be re-saved. Non-default values the
user set deliberately are still emitted.

internal/util/link/outbound.go

@@ -545,9 +545,11 @@ func buildStream(network, security string) map[string]any {
 	case "httpupgrade":
 		stream["httpupgradeSettings"] = map[string]any{"path": "/", "host": "", "headers": map[string]any{}}
 	case "xhttp":
+		// No scMaxEachPostBytes/scMinPostsIntervalMs seed: xray-core's own
+		// defaults apply, and the literal values fingerprint traffic (#5141).
 		stream["xhttpSettings"] = map[string]any{
 			"path": "/", "host": "", "mode": "auto", "headers": map[string]any{},
-			"xPaddingBytes": "100-1000", "scMaxEachPostBytes": "1000000",
+			"xPaddingBytes": "100-1000",
 		}
 	default:
 		stream["tcpSettings"] = map[string]any{"header": map[string]any{"type": "none"}}