feat(mtproto): adopt dolonet/mtg-multi and make MTProto inbounds multi-client

Replace the upstream 9seconds/mtg sidecar with the dolonet/mtg-multi fork so a single MTProto inbound can serve many per-user secrets. Each panel client is now one named FakeTLS secret in the fork's [secrets] section: clients are first-class (attach/detach, limits, expiry, per-client tg:// links) exactly like every other protocol, mirroring the WireGuard multi-client model. Per-client traffic and online status come from the fork's /stats JSON API (its Prometheus output has no per-user label), fed into the existing email-keyed client_traffics accumulator; an optional throttle caps concurrent connections. A one-time seeder converts each legacy single-secret inbound into a one-client inbound.

The fork ships only linux/darwin amd64/arm64 binaries but is pure Go, so provisioning builds it from source for every supported platform (release.yml, DockerInit.sh) while keeping the panel-expected mtg-<os>-<arch> filename and the 'run' verb, so process.go is untouched. Also fixes a pre-existing update.sh gap that never renamed the mtg binary for armv6/armv7 updates.

frontend/src/generated/zod.ts

@@ -258,6 +258,7 @@ export const ClientSchema = z.object({
   publicKey: z.string().optional(),
   reset: z.number().int(),
   reverse: z.lazy(() => ClientReverseSchema).nullable().optional(),
+  secret: z.string().optional(),
   security: z.string(),
   subId: z.string(),
   tgId: z.number().int(),
@@ -293,6 +294,7 @@ export const ClientRecordSchema = z.object({
   publicKey: z.string(),
   reset: z.number().int(),
   reverse: z.unknown(),
+  secret: z.string(),
   security: z.string(),
   subId: z.string(),
   tgId: z.number().int(),
@@ -423,6 +425,7 @@ export const InboundOptionSchema = z.object({
   enable: z.boolean(),
   id: z.number().int(),
   listen: z.string().optional(),
+  mtprotoDomain: z.string().optional(),
   nodeAddress: z.string().optional(),
   nodeId: z.number().int().nullable().optional(),
   port: z.number().int(),