Add provision_printer and remove_printer to the gateway protocol

Adding a printer from the console has to put its LAN credential on the
gateway without the cloud keeping it. The new server messages carry it once
(documented as never-log) and are answered through the existing
command_result with the request id. The message cannot name a certificate
path or serial port: those are on the gateway's own disk and USB bus.

packages/ts-types/src/schemas/edge.ts

@@ -374,5 +374,45 @@ export const EdgeServerMessageSchema = Type.Union([
     printer_id: Type.String(),
     command: PrinterCommandSchema,
   }),
+  /**
+   * Add a printer to this gateway. Relayed by the cloud, which keeps nothing:
+   * it carries the printer's LAN credential, and printer credentials never
+   * rest in the cloud. The gateway verifies them by connecting, stores them
+   * in its own database, and answers with a `command_result` whose
+   * `command_id` is `request_id`. **Never log this message.**
+   *
+   * No `ca_cert_path` and no serial port on purpose: both name things on the
+   * gateway's own disk and USB bus, which the cloud does not get to choose.
+   */
+  Type.Object(
+    {
+      type: Type.Literal("provision_printer"),
+      request_id: Type.String(),
+      printer: Type.Object(
+        {
+          /** The gateway's own printer id, chosen by the cloud. */
+          id: Type.String({ pattern: "^[A-Za-z0-9_-]{1,64}$" }),
+          name: Type.String({ minLength: 1, maxLength: 200 }),
+          vendor: Type.String(),
+          host: Type.Optional(Type.String({ maxLength: 255 })),
+          access_code: Type.Optional(Type.String({ maxLength: 128 })),
+          sn: Type.Optional(Type.String({ maxLength: 64 })),
+          api_key: Type.Optional(Type.String({ maxLength: 256 })),
+        },
+        { additionalProperties: false },
+      ),
+    },
+    { additionalProperties: false },
+  ),
+  /** Forget a printer: leave the running fleet and delete its stored credential. */
+  Type.Object(
+    {
+      type: Type.Literal("remove_printer"),
+      request_id: Type.String(),
+      /** The gateway's own printer id. */
+      printer_id: Type.String(),
+    },
+    { additionalProperties: false },
+  ),
 ]);
 export type EdgeServerMessage = Static<typeof EdgeServerMessageSchema>;