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/web/service/xray.go

@@ -121,6 +121,10 @@ func (s *XrayService) GetXrayConfig() (*xray.Config, error) {
 	xrayConfig.API = ensureAPIServices(xrayConfig.API)
 	xrayConfig.Policy = ensureStatsPolicy(xrayConfig.Policy)
 	xrayConfig.RouterConfig = stripDisabledRules(xrayConfig.RouterConfig)
+	// Template outbounds authored before the xray-core #6258 XHTTP rename may
+	// still carry sessionPlacement/sessionKey; lift them too (same reason as
+	// the per-inbound lift below).
+	xrayConfig.OutboundConfigs = liftOutboundsXhttpSessionIDKeys(xrayConfig.OutboundConfigs)
 
 	_, _, _ = s.inboundService.AddTraffic(nil, nil)
 
@@ -251,6 +255,12 @@ func (s *XrayService) GetXrayConfig() (*xray.Config, error) {
 
 			delete(stream, "externalProxy")
 
+			// xray-core v26.6.22 (#6258) renamed the XHTTP session keys and
+			// kept no fallback. Lift legacy sessionPlacement/sessionKey onto the
+			// new names here so inbounds stored before the rename keep working
+			// without the admin re-saving them.
+			liftXhttpSessionIDKeys(stream)
+
 			newStream, err := json.MarshalIndent(stream, "", "  ")
 			if err != nil {
 				return nil, err
@@ -576,7 +586,7 @@ func mergeSubscriptionOutbounds(cfg *xray.Config, prepend, appendList []any) {
 			return
 		}
 	}
-	merged := make([]any, 0, len(prepend)+len(templateOutbounds)+len(appendList))
+	var merged []any
 	merged = append(merged, prepend...)
 	merged = append(merged, templateOutbounds...)
 	merged = append(merged, appendList...)
@@ -1078,3 +1088,60 @@ func (s *XrayService) IsNeedRestartAndSetFalse() bool {
 func (s *XrayService) DidXrayCrash() bool {
 	return !s.IsXrayRunning() && !isManuallyStopped.Load()
 }
+
+// liftXhttpSessionIDKeys renames the legacy XHTTP session keys
+// (sessionPlacement/sessionKey) to the v26.6.22 #6258 names
+// (sessionIDPlacement/sessionIDKey) inside a streamSettings map. xray-core kept
+// no fallback for the old names, so a config stored before the rename would be
+// silently ignored by the engine. Returns true if it changed anything.
+func liftXhttpSessionIDKeys(stream map[string]any) bool {
+	xhttp, ok := stream["xhttpSettings"].(map[string]any)
+	if !ok {
+		return false
+	}
+	changed := false
+	for legacy, renamed := range map[string]string{
+		"sessionPlacement": "sessionIDPlacement",
+		"sessionKey":       "sessionIDKey",
+	} {
+		v, has := xhttp[legacy]
+		if !has {
+			continue
+		}
+		if _, exists := xhttp[renamed]; !exists {
+			xhttp[renamed] = v
+		}
+		delete(xhttp, legacy)
+		changed = true
+	}
+	return changed
+}
+
+// liftOutboundsXhttpSessionIDKeys applies liftXhttpSessionIDKeys to every
+// outbound's streamSettings in the raw outbounds array. The original bytes are
+// returned untouched when nothing needs lifting, so an unchanged config never
+// looks modified to the hot-reload diff.
+func liftOutboundsXhttpSessionIDKeys(raw json_util.RawMessage) json_util.RawMessage {
+	if len(raw) == 0 {
+		return raw
+	}
+	var outbounds []map[string]any
+	if err := json.Unmarshal(raw, &outbounds); err != nil {
+		return raw
+	}
+	changed := false
+	for _, ob := range outbounds {
+		if stream, ok := ob["streamSettings"].(map[string]any); ok {
+			if liftXhttpSessionIDKeys(stream) {
+				changed = true
+			}
+		}
+	}
+	if !changed {
+		return raw
+	}
+	if rewritten, err := json.Marshal(outbounds); err == nil {
+		return rewritten
+	}
+	return raw
+}