feat(reality): derive a stable per-client spiderX for shared links

The inbound's spiderX now acts as a per-client seed: exports emit
sha256(seed|subKey) truncated to a 15-hex "/path", so a client's spx no
longer changes on every subscription fetch (#5718) while different
clients stop sharing one fingerprintable value. The form gains a
regenerate button that rotates every client's path at once.

The frontend link builders derive through the same function
(lib/xray/spider-x.ts, @noble/hashes) keyed on subId-then-email like
the Go subKey, so panel QR/copy links and subscription output agree —
cross-language vector tests lock both sides byte-for-byte. streamData
now tolerates malformed stored stream settings (unparseable JSON, null
tls/reality settings) instead of panicking the subscription request.

internal/web/translation/zh-CN.json

@@ -666,6 +666,7 @@
         "scanUse": "使用",
         "scanRescan": "重新扫描",
         "spiderX": "SpiderX",
+        "spiderXHint": "按客户端的种子——面板据此为每个客户端派生唯一的 spx 路径；重新生成可轮换所有客户端的路径",
         "getNewCert": "获取新证书",
         "mldsa65Seed": "mldsa65 Seed",
         "mldsa65Verify": "mldsa65 Verify",