Fix discrepancies between Node and Proxy recording modes.

[Joerger]

Changes:

• Remove the unique ID from the ephemeral forwarding server, which provided no benefit. Instead, the ID of the server will be the Node ID. Combined with the forwarded_by: <proxy_id> field in events, it will be clear that the actual component being connected to is the ephemeral forwarding server for that node session.
• Rename the forwarding server field hostUUID to proxyUUID for clarity. HostUUID() still returns the same proxy uuid.
• Update the forwarding server GetInfo method to return the full end server info, including labels, subkind, etc.
  • Build event metadata from the server info from GetInfo. This eliminates some of the discrepancies I found between the events and the actual server info, and between the forwarding vs. node recording events.

Adapted from #52920

Depends on #58700

Closes #4146

Diff between Node recordings before and after this PR:

{
  "addr.remote": "127.0.0.1:52234",
  "cluster_name": "root.example.com",
  "code": "T2000I",
  "ei": 0,
  "event": "session.start",
  "initial_command": [
    ""
  ],
  "login": "bjoerger",
  "namespace": "default",
  "private_key_policy": "none",
  "proto": "ssh",
  "server_hostname": "node",
  "server_id": "978e143e-6271-4ff0-8344-3d71528615b1",
  "server_labels": {
    "arch": "arm",
    "cluster": "root.example.com",
    "env": "production",
    "hostname": "Brians-MacBook-Pro-2.local"
  },
+ "server_sub_kind": "teleport",
  "server_version": "19.0.0-dev",
  "session_recording": "node",
  "sid": "7f3da66e-eab4-437f-bc96-65cf40363d18",
  "size": "167:23",
  "time": "2025-09-03T21:29:50.374Z",
  "uid": "0ae3ecae-1f57-4436-8493-60a24870a932",
  "user": "dev",
  "user_kind": 1
}

Diff between Proxy recordings before and after this PR:

{
  "addr.remote": "127.0.0.1:52863",
  "cluster_name": "root.example.com",
  "code": "T2000I",
  "ei": 0,
  "event": "session.start",
  "forwarded_by": "7dae42bb-6401-405f-b683-efa44d57e484",
  "initial_command": [
    ""
  ],
  "login": "bjoerger",
  "namespace": "default",
  "private_key_policy": "none",
  "proto": "ssh",
- "server_addr": "@local-node",
  "server_hostname": "node",
- "server_id": "7f4ce963-f184-4fe7-a0fe-13f35a7d9e42.root.example.com",
+ "server_id": "7f4ce963-f184-4fe7-a0fe-13f35a7d9e42",
+ "server_labels": {
+   "arch": "arm",
+   "cluster": "root.example.com",
+   "env": "production",
+   "hostname": "Brians-MacBook-Pro-2.local"
+ },
  "server_sub_kind": "teleport",
  "server_version": "19.0.0-dev",
  "session_recording": "proxy",
  "sid": "00e55c91-7bd3-48e7-96c4-30e17d78da2f",
  "size": "167:23",
  "time": "2025-09-03T21:47:12.505Z",
  "uid": "995f48d4-684c-4d72-bfa8-cd52ac00bab4",
  "user": "dev",
  "user_kind": 1
}

Diff between Node and Proxy recordings after this PR:

{
  "addr.remote": "127.0.0.1:52562",
  "cluster_name": "root.example.com",
  "code": "T2000I",
  "ei": 0,
  "event": "session.start",
+ "forwarded_by": "1d3f9f84-3f63-4267-be51-0fae1e2fe4b0",
  "initial_command": [
    ""
  ],
  "login": "bjoerger",
  "namespace": "default",
  "private_key_policy": "none",
  "proto": "ssh",
  "server_hostname": "node",
  "server_id": "27a558dd-2d35-407c-bfcc-3333dca34b48",
  "server_labels": {
    "arch": "arm",
    "cluster": "root.example.com",
    "env": "production",
    "hostname": "Brians-MacBook-Pro-2.local"
  },
  "server_sub_kind": "teleport",
  "server_version": "19.0.0-dev",
- "session_recording": "node",
+ "session_recording": "proxy",
  "sid": "3a1c8d5b-9719-4df2-ac6a-12191062d8eb",
  "size": "167:23",
  "time": "2025-09-03T21:34:45.056Z",
  "uid": "9dd08c52-7f68-4a03-b827-bb3230e76c43",
  "user": "dev",
  "user_kind": 1
}

Diff between Node and Proxy recordings after this PR, connecting to node w/o tunnel mode:

{
- "addr.local": "127.0.0.1:3080",
+ "addr.local": "127.0.0.1:3022",
  "addr.remote": "127.0.0.1:53139",
  "cluster_name": "root.example.com",
  "code": "T2000I",
  "ei": 0,
  "event": "session.start",
+ "forwarded_by": "7dae42bb-6401-405f-b683-efa44d57e484",
  "initial_command": [
    ""
  ],
  "login": "bjoerger",
  "namespace": "default",
  "private_key_policy": "none",
  "proto": "ssh",
- "server_addr": "[::]:3022",
+ "server_addr": "127.0.0.1:3022",
  "server_hostname": "server01",
  "server_id": "7dae42bb-6401-405f-b683-efa44d57e484",
  "server_labels": {
    "arch": "arm",
    "cluster": "root.example.com",
    "env": "staging",
    "hostname": "Brians-MacBook-Pro-2.local",
    "idp_1": "access_teleport_template",
    "oidc-client-id": "dev"
  },
  "server_sub_kind": "teleport",
  "server_version": "19.0.0-dev",
- "session_recording": "node",
+ "session_recording": "proxy",
  "sid": "bd6a3988-8f28-40a8-a4fd-464382e11a42",
  "size": "167:33",
  "time": "2025-09-03T22:03:14.344Z",
  "uid": "6dfa4428-09d3-405f-827b-794efb5ec6e0",
  "user": "dev",
  "user_kind": 1
}

[Joerger]

@doggydogworld Friendly ping to review

[Joerger]

Reopened... this got automatically closed due to a faulty rebase (git machete) that reset the branch to master.

[Joerger]

@doggydogworld @zmb3 Friendly ping to review

[backport-bot-workflows]

@Joerger See the table below for backport results.

Branch	Result
branch/v16	Failed
branch/v17	Failed
branch/v18	Failed