docs: Add WinSCP troubleshooting step and tsh.exe path advice

docs/pages/connect-your-client/putty-winscp.mdx

@@ -27,6 +27,15 @@ You will learn how to:
 
   You should then unzip the archive and move `tsh.exe` to your `%PATH%`.
 
+  <Admonition type="note">
+    Do not place `tsh.exe` in the `System32` directory, as this can cause issues when using WinSCP.
+    You should use `%SystemRoot%` (e.g. `C:\Windows`) instead, which is already included in `%PATH`.
+
+    If you do not have administrator rights on the Windows system you're using, you can use `%USERPROFILE%`
+    (e.g. `C:\Users\<username>`) instead - but note that you will not be able to run `tsh` commands globally
+    from the command line unless you are in the same directory as `tsh.exe`.
+  </Admonition>
+
 - PuTTY for Windows version 0.78 or higher. You can download the latest version of PuTTY from the [PuTTY download page](https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html).
 
 - (optional) WinSCP for Windows version 6.2 or higher. You can download the latest version of WinSCP from the [WinSCP download page](https://winscp.net/eng/download.php)
@@ -284,13 +293,37 @@ key. Note that if you re-run `tsh puttyconfig` for the given hostname, this comm
 
 ## Troubleshooting
 
+### WinSCP shows `Server unexpectedly closed network connection` or `Error 232: The pipe is being closed` when connecting
+
+This error is usually caused when the `tsh.exe` application is incorrectly placed in the `C:\Windows\System32` directory. This
+triggers a bug in WinSCP which causes the path to `tsh.exe` to be erroneously replaced at runtime, leading to a connection
+failure. This bug does not seem to affect PuTTY sessions.
+
+Here are two locations where `tsh.exe` can be stored which are not affected by this bug:
+- `%USERPROFILE` (e.g. `C:\Users\<username>` - does not require administrator privileges)
+- `%WINDIR%` (e.g. `C:\Windows` - requires administrator privileges)
+
+To fix this issue, follow these steps:
+1. Place the `tsh.exe` application into a different directory, as detailed above.
+1. Re-run `tsh puttyconfig` for each PuTTY session in order to replace the configured path to `tsh.exe` inside the session.
+1. Delete each saved session inside WinSCP.
+1. Re-import saved PuTTY sessions into WinSCP by following the process detailed in steps 2-3 above.
+
 ### `proxy: ERROR: access denied to <user> connecting to <proxy>`
 
 You have provided an incorrect login username to the `tsh puttyconfig` command. Re-run the command with a login username
 that your Teleport user/role has permissions to use. Check the logins listed under the `logins` role specification or user trait.
 
 If you can log in successfully with `tsh ssh`, you should be able to use the name login/hostname with `tsh puttyconfig`.
 
+### `Connect failed [ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain]`
+
+You have provided an incorrect login username to the `tsh puttyconfig` command when attempting to connect to an OpenSSH server.
+Re-run the command with a login username that your Teleport user/role has permissions to use. Check the logins listed under the
+`logins` role specification or user trait.
+
+If you can log in successfully with `tsh ssh`, you should be able to use the name login/hostname with `tsh puttyconfig`.
+
 ### `proxy: ERROR: ssh: subsystem request failed`
 
 The Teleport proxy is unable to connect to the given host/port provided in the saved session. This may mean that the node is
@@ -300,6 +333,15 @@ successful, check the Teleport proxy logs for more detailed errors.
 If the node is running OpenSSH rather than Teleport, you must make sure to specify the `sshd` port when adding the session,
 for example using `tsh puttyconfig --port 22 user@host` or `tsh puttyconfig user@host:22`.
 
+### `proxy: direct dialing to nodes not found in inventory is not supported`
+
+This error usually means that you registered an agentless OpenSSH host (i.e. a host running sshd) without also providing the
+port while running `tsh puttyconfig`. Try re-adding the host with the correct port (22 in this example) by using
+`tsh puttyconfig --port 22 user@host`.
+
+If you still get this error after fixing the port, make sure that the host you are trying to connect to appears in the output
+of `tsh ls`. Hostnames which do not appear in the output of `tsh ls` are unavailable for connection.
+
 ### `Unable to use certificate file "C:\Users\<username>\.tsh\keys\<proxy>\<user>-ssh\<cluster>-cert.pub" (unable to open file)`
 
 You are not logged into Teleport correctly. Run `tsh login --proxy=<proxy hostname>` to get valid certificates before

docs/pages/includes/install-tsh.mdx

@@ -1,7 +1,7 @@
 <Tabs>
   <TabItem label="Mac">
     Download the signed macOS .pkg installer for `tsh`. In Finder double-click the `pkg` file to install it:
- 
+
     ```code
     $ curl -O https://cdn.teleport.dev/tsh-(=teleport.version=).pkg
     ```
@@ -28,6 +28,8 @@
     ```code
     $ curl.exe -O https://cdn.teleport.dev/teleport-v(=teleport.version=)-windows-amd64-bin.zip
     # Unzip the archive and move `tsh.exe` to your %PATH%
+    # NOTE: Do not place tsh.exe in the System32 directory, as this can cause issues when using WinSCP.
+    # Use %WINDIR% (C:\Windows) or %USERPROFILE% (C:\Users\<username>) instead.
     ```
   </TabItem>
 

docs/pages/includes/install-windows-clients.mdx

@@ -27,3 +27,8 @@
   ```
 
   Make sure to move `tsh.exe` and `tctl.exe` into your PATH.
+
+  <Admonition type="note">
+    Do not place `tsh.exe` in the `System32` directory, as this can cause issues when using WinSCP.
+    You should use `%WINDIR%` (e.g. `C:\Windows`) or `%USERPROFILE%` (e.g. `C:\Users\<username>`) instead.
+  </Admonition>

docs/pages/server-access/guides/jetbrains-sftp.mdx

@@ -73,7 +73,7 @@ $ ssh user@[server name].[cluster name]
   $ ssh -p 22 user@[server name].[cluster name]
   ```
 </Admonition>
-  
+
 ## Step 2/3. Configure your JetBrains IDE
 
 After opening your IDE go to `Tools` -> `Deployment` -> `Browse Remote Host`.