Add Enable/Disable Toggle for Xray Routing Rules (#5296)

* feat: add enable/disable toggle for xray routing rules

* fix(routing): never let the internal api rule be disabled

The Enable/Disable toggle could strip the stats api rule: its table
switch was locked, but the rule-form modal's Enable dropdown was not,
and stripDisabledRules had no api-rule guard (EnsureStatsRouting's
delete only runs when the api rule isn't already first). A disabled
api rule then dropped out of the generated config and broke traffic
accounting.

- stripDisabledRules now always keeps the api rule, even if marked
  disabled, and strips the panel-only enabled key from every rule
- extract isApiRule helper (backend + frontend) and reuse it across
  the table switch, card switch, and form modal
- disable the form-modal Enable dropdown for the api rule
- add stripDisabledRules tests covering the api-rule survival path

---------

Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>

frontend/src/schemas/routing.ts

@@ -17,6 +17,7 @@ export type RuleWebhook = z.infer<typeof RuleWebhookSchema>;
 
 export const RuleObjectSchema = z.object({
   type: z.literal('field').default('field'),
+  enabled: z.boolean().optional(),
   domain: z.array(z.string()).optional(),
   ip: z.array(z.string()).optional(),
   port: PortValueSchema.optional(),