feat(xhttp): support sessionID* rename + sessionIDTable/Length (xray v26.6.22) (#5506)

* feat(xhttp): support sessionID* rename + sessionIDTable/Length (xray v26.6.22)

xray-core v26.6.22 (PR #6258) renamed the XHTTP session config keys
sessionPlacement/sessionKey to sessionIDPlacement/sessionIDKey (no fallback
kept in core) and added sessionIDTable (predefined charset name or literal
ASCII) and sessionIDLength (range, e.g. 16-32, lower bound > 0).

Panel changes:
- Schema (xhttp.ts): rename the two keys, add sessionIDTable/sessionIDLength,
  and a z.preprocess that lifts legacy keys off stored configs so an upgraded
  panel never silently drops a saved session setting.
- Wire normalize + share-link build/parse: rename keys, emit the two new
  fields, and accept legacy sessionPlacement/sessionKey from old share links.
- Inbound + outbound XHTTP forms: rename field paths, add a sessionIDTable
  autocomplete (9 predefined tables + free ASCII) and a sessionIDLength range
  input shown only when a table is set, with light client validation (ASCII
  table, length min > 0; xray enforces the room-size minimum server-side).
- Subscription (service.go) and Clash (clash_service.go) builders: emit the
  renamed + new keys, with a legacy fallback for not-yet-resaved inbounds.
- Locales: add sessionIDTable/sessionIDLength labels + hints in all 13 files.

Two sibling v26.6.22 XHTTP commits need no panel change and are covered by the
core bump alone: #6332 (XHTTP/3 closes QUIC/UDP) and #6320 (udpHop honors the
existing dialerProxy).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* test(xhttp): add Session ID Table to inbound form-blocks snapshot

The new sessionIDTable input renders by default in the inbound XHTTP form, so
its label joins the field-structure snapshot. sessionIDLength stays conditional
(only shown when a table is set), so it does not appear here.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(xhttp): migrate legacy session keys in the running xray config

The Zod preprocess plus the subscription/Clash fallbacks only covered the
panel UI and share-link output. The config handed to the running xray-core
process is built from the raw stored streamSettings in GetXrayConfig, which
did not rewrite the renamed XHTTP session keys — so a pre-upgrade inbound (or
template outbound) stored with a non-default sessionPlacement was emitted
unchanged and dropped by xray-core v26.6.22, until the admin re-saved it.

Lift sessionPlacement/sessionKey onto sessionIDPlacement/sessionIDKey at
config-generation time, in the existing inbound stream-rewrite block (next to
the tls/reality/externalProxy handling) and across template outbounds. The
lift is idempotent and leaves unchanged configs byte-identical so the
hot-reload diff never sees a spurious change.

Also tighten validateSessionIDLength to reject an inverted range (e.g. 32-16)
in addition to the existing lower-bound > 0 check.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(xray): avoid summed-capacity allocation in mergeSubscriptionOutbounds

CodeQL go/allocation-size-overflow flagged the pre-sized make() whose
capacity was a sum of three slice lengths. Grow the slice via append on
a nil slice instead; same result, no overflow-prone capacity expression.

frontend/src/test/__snapshots__/inbound-form-blocks.test.tsx.snap

@@ -118,6 +118,7 @@ exports[`inbound transport forms > XhttpForm field structure is stable 1`] = `
   "Uplink HTTP Method",
   "Padding Obfs Mode",
   "Session Placement",
+  "Session ID Table",
   "Sequence Placement",
   "No SSE Header",
   "XMUX",

frontend/src/test/__snapshots__/stream.test.ts.snap

@@ -53,8 +53,10 @@ exports[`NetworkSettingsSchema fixtures > parses xhttp-basic byte-stably 1`] = `
     "seqKey": "",
     "seqPlacement": "",
     "serverMaxHeaderBytes": 0,
-    "sessionKey": "",
-    "sessionPlacement": "",
+    "sessionIDKey": "",
+    "sessionIDLength": "",
+    "sessionIDPlacement": "",
+    "sessionIDTable": "",
     "uplinkChunkSize": 0,
     "uplinkDataKey": "",
     "uplinkDataPlacement": "",
@@ -87,8 +89,10 @@ exports[`NetworkSettingsSchema fixtures > parses xhttp-extra-padding byte-stably
     "seqKey": "",
     "seqPlacement": "",
     "serverMaxHeaderBytes": 0,
-    "sessionKey": "",
-    "sessionPlacement": "",
+    "sessionIDKey": "",
+    "sessionIDLength": "",
+    "sessionIDPlacement": "",
+    "sessionIDTable": "",
     "uplinkChunkSize": 0,
     "uplinkDataKey": "",
     "uplinkDataPlacement": "",
@@ -121,8 +125,10 @@ exports[`NetworkSettingsSchema fixtures > parses xhttp-extra-placement byte-stab
     "seqKey": "X-Seq",
     "seqPlacement": "cookie",
     "serverMaxHeaderBytes": 0,
-    "sessionKey": "X-Session",
-    "sessionPlacement": "header",
+    "sessionIDKey": "X-Session",
+    "sessionIDLength": "",
+    "sessionIDPlacement": "header",
+    "sessionIDTable": "",
     "uplinkChunkSize": 0,
     "uplinkDataKey": "u",
     "uplinkDataPlacement": "query",
@@ -158,8 +164,10 @@ exports[`NetworkSettingsSchema fixtures > parses xhttp-extra-tuning byte-stably
     "seqKey": "",
     "seqPlacement": "",
     "serverMaxHeaderBytes": 16384,
-    "sessionKey": "",
-    "sessionPlacement": "",
+    "sessionIDKey": "",
+    "sessionIDLength": "",
+    "sessionIDPlacement": "",
+    "sessionIDTable": "",
     "uplinkChunkSize": 8192,
     "uplinkDataKey": "",
     "uplinkDataPlacement": "",