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.

internal/sub/clash_service_test.go

@@ -330,8 +330,10 @@ func TestBuildXhttpClashOpts_FullFieldMapping(t *testing.T) {
 		"xPaddingPlacement":    "queryInHeader",
 		"xPaddingMethod":       "tokenish",
 		"uplinkHTTPMethod":     "POST",
-		"sessionPlacement":     "query",
-		"sessionKey":           "sess",
+		"sessionIDPlacement":   "query",
+		"sessionIDKey":         "sess",
+		"sessionIDTable":       "Base62",
+		"sessionIDLength":      "16-32",
 		"seqPlacement":         "header",
 		"seqKey":               "seq",
 		"uplinkDataPlacement":  "body",
@@ -377,11 +379,17 @@ func TestBuildXhttpClashOpts_FullFieldMapping(t *testing.T) {
 	if opts["uplink-http-method"] != "POST" {
 		t.Errorf("uplink-http-method = %v", opts["uplink-http-method"])
 	}
-	if opts["session-placement"] != "query" {
-		t.Errorf("session-placement = %v", opts["session-placement"])
+	if opts["session-id-placement"] != "query" {
+		t.Errorf("session-id-placement = %v", opts["session-id-placement"])
 	}
-	if opts["session-key"] != "sess" {
-		t.Errorf("session-key = %v", opts["session-key"])
+	if opts["session-id-key"] != "sess" {
+		t.Errorf("session-id-key = %v", opts["session-id-key"])
+	}
+	if opts["session-id-table"] != "Base62" {
+		t.Errorf("session-id-table = %v", opts["session-id-table"])
+	}
+	if opts["session-id-length"] != "16-32" {
+		t.Errorf("session-id-length = %v", opts["session-id-length"])
 	}
 	if opts["seq-placement"] != "header" {
 		t.Errorf("seq-placement = %v", opts["seq-placement"])