docs(pwsh): guard profile initialization

Keep synced profiles quiet when Oh My Posh is not installed and establish
UTF-8 console input and output before loading the prompt integration.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 30a4d06b-a9a5-4176-b3f2-8c554e037e21

Author: crutkas

website/docs/installation/prompt.mdx

@@ -217,16 +217,18 @@ to only require remote scripts to be signed using `Set-ExecutionPolicy -Executio
 Add the following snippet as the last line to your PowerShell profile script:
 
 ```powershell
-oh-my-posh init pwsh | Invoke-Expression
+$(if (Get-Command 'oh-my-posh' -ErrorAction Ignore) {
+    oh-my-posh init pwsh
+    # Set output encoding to UTF-8
+    [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+    # Set input encoding to UTF-8 (for reading user input with non-ASCII chars)
+    [Console]::InputEncoding = [System.Text.Encoding]::UTF8
+}) | Invoke-Expression
 ```
 
 :::tip Execution policy
 In case the execution policy disables executing unsigned scripts on your system, you can fallback to evaluating
-the script instead. Use the `--eval` flag to do so:
-
-```powershell
-oh-my-posh init pwsh --eval | Invoke-Expression
-```
+the script instead. Add the `--eval` flag to the `oh-my-posh init pwsh` command above.
 
 Be aware this will make initializing the shell slower.
 :::

website/static/skills/ohmyposh/shell/powershell.md

@@ -18,7 +18,13 @@ notepad $PROFILE
 Add this as the **last line**:
 
 ```powershell
-oh-my-posh init pwsh | Invoke-Expression
+$(if (Get-Command 'oh-my-posh' -ErrorAction Ignore) {
+    oh-my-posh init pwsh
+    # Set output encoding to UTF-8
+    [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+    # Set input encoding to UTF-8 (for reading user input with non-ASCII chars)
+    [Console]::InputEncoding = [System.Text.Encoding]::UTF8
+}) | Invoke-Expression
 ```
 
 Reload the profile:
@@ -35,11 +41,7 @@ Reload the profile:
 Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope LocalMachine
 ```
 
-Or use the `--eval` flag (slightly slower startup):
-
-```powershell
-oh-my-posh init pwsh --eval | Invoke-Expression
-```
+Or add the `--eval` flag to the `oh-my-posh init pwsh` command above (slightly slower startup).
 
 ## Next step