feat(daemon): publish room member statistics over RPC and the CLI

The statistics parsed from the JoinRoom reply were reachable only from the
library. They answer the question `room users` already exists to ask -- who
is in here, and are they worth downloading from -- so they belong on its
output rather than behind a second call.

- proto: room.member_stats, with a RoomUserStatsDto carrying status, share
  counts, free slots and country
- SessionApi::room_member_stats, so local and remote sessions stay
  interchangeable; the status word is decoded through one shared helper
  rather than a third copy of the match
- `room users` now emits status, average_speed, shared_files,
  shared_folders, slots_free and country, each null when the server said
  nothing, documented in SKILL.md
- docs/openrpc.json regenerated from the wire types

soulseek-rs/docs/openrpc.json

@@ -525,6 +525,21 @@
         ],
         "type": "object"
       },
+      "MemberStats": {
+        "description": "What the server said about each member of a room when it was joined.",
+        "properties": {
+          "members": {
+            "items": {
+              "$ref": "#/components/schemas/RoomUserStatsDto"
+            },
+            "type": "array"
+          }
+        },
+        "required": [
+          "members"
+        ],
+        "type": "object"
+      },
       "Members": {
         "properties": {
           "users": {
@@ -733,6 +748,53 @@
         ],
         "type": "object"
       },
+      "RoomUserStatsDto": {
+        "description": "One member of a room, as the JoinRoom reply described them.",
+        "properties": {
+          "average_speed": {
+            "format": "uint32",
+            "minimum": 0,
+            "type": "integer"
+          },
+          "country": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "shared_files": {
+            "format": "uint32",
+            "minimum": 0,
+            "type": "integer"
+          },
+          "shared_folders": {
+            "format": "uint32",
+            "minimum": 0,
+            "type": "integer"
+          },
+          "slots_free": {
+            "format": "uint32",
+            "minimum": 0,
+            "type": "integer"
+          },
+          "status": {
+            "description": "`online`, `away`, or `offline`.",
+            "type": "string"
+          },
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username",
+          "status",
+          "average_speed",
+          "shared_files",
+          "shared_folders",
+          "slots_free"
+        ],
+        "type": "object"
+      },
       "SayParams": {
         "properties": {
           "message": {
@@ -1776,6 +1838,26 @@
       },
       "summary": "Who is currently in a room."
     },
+    {
+      "name": "room.member_stats",
+      "paramStructure": "by-name",
+      "params": [
+        {
+          "name": "room",
+          "required": true,
+          "schema": {
+            "type": "string"
+          }
+        }
+      ],
+      "result": {
+        "name": "result",
+        "schema": {
+          "$ref": "#/components/schemas/MemberStats"
+        }
+      },
+      "summary": "What the server said about each member of a joined room."
+    },
     {
       "name": "message.send",
       "paramStructure": "by-name",