feat(clients): bind host rules to individual clients in subscriptions (#6620)

Host rules applied per inbound only, so every client of an inbound got the same
subscription endpoints (#6618). A client can now be bound to one or more host
rules, and its raw, JSON and Clash subscriptions render only those hosts, in
either subscription order; an unbound client is unchanged. A binding whose hosts
are deleted, disabled or excluded from the format fails closed: the client gets
no links there but stays in traffic accounting. Host edits keep row ids, so
bindings survive them; nil leaves a stored binding alone and an empty list
clears it.

frontend/src/generated/zod.ts

@@ -434,6 +434,7 @@ export const ClientSchema = z.object({
   allowedIPs: z.array(z.string()).optional(),
   allowedIPsByInbound: z.record(z.number().int(), z.array(z.string())).optional(),
   auth: z.string().optional(),
+  clientHostRuleIds: z.array(z.number().int()).optional(),
   comment: z.string(),
   created_at: z.number().int().optional(),
   email: z.string(),
@@ -488,6 +489,7 @@ export const ClientRecordSchema = z.object({
   adTag: z.string(),
   allowedIPs: z.string(),
   auth: z.string(),
+  clientHostRuleIds: z.array(z.number().int()).optional(),
   comment: z.string(),
   createdAt: z.number().int(),
   email: z.string(),