Add OSC 133 shell integration sequences for Windows Terminal PowerShell support

[Copilot]

Windows Terminal supports OSC 133 escape sequences (\x1b]133;A\a, \x1b]133;B\a, \x1b]133;C\a) for shell integration, enabling command navigation, selection, and visual separators. Cmder already supports OSC 9;9 for directory tracking—this adds OSC 133 support for PowerShell sessions.

Changes

vendor/profile.ps1

• OSC 133;A (line 231): Emitted before prompt rendering to mark prompt start
• OSC 133;B (line 246): Emitted after prompt to mark command input start
• OSC 133;C (line 109): Emitted via PSReadLine Enter handler to mark command output start

README.md

• Documented shell integration support alongside existing OSC 9;9 documentation

Implementation

All sequences conditionally emit only when $env:WT_SESSION is set, ensuring no interference with ConEmu or other terminals:

# OSC 133;A - marks start of prompt
if ($env:WT_SESSION) {
    Microsoft.PowerShell.Utility\Write-Host -NoNewline "$([char]27)]133;A$([char]7)"
}

# OSC 133;C - marks start of command output (via PSReadLine)
if ($env:WT_SESSION) {
    Set-PSReadLineKeyHandler -Key Enter -ScriptBlock {
        [Microsoft.PowerShell.PSConsoleReadLine]::AcceptLine()
        [Console]::Write("$([char]27)]133;C$([char]7)")
    }
}

Follows existing OSC 9;9 pattern for consistency.

Original prompt

Why Windows Terminal support these codes, what they are, and do we need to add them in Cmder's PowerShell profile as well?

"\x1b]133;A\a"
"\x1b]133;B\a"
"\x1b]133;C\a"

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