feat(powershell): add rtk powershell command family for Windows cmdlets

[phatphamhong-tech]

Summary

• Adds rtk powershell <Cmdlet> [args...], filtering output for 16 commonly-used
  PowerShell cmdlets (Get-ChildItem, Get-Process, Get-Service, Get-Content,
  Select-String, Get-WinEvent, Get-EventLog, Get-ItemProperty, Test-NetConnection,
  Get-NetAdapter, Get-NetTCPConnection, Get-ComputerInfo, Get-Package, Get-Counter,
  Install-Package, Get-Item), same header+capped-rows / essential-properties
  approach as the rest of rtk. Cmdlets with already-minimal or side-effecting
  output pass straight through unfiltered, like rtk proxy.
• Untrusted input never reaches the PowerShell script as text: the unknown-cmdlet
  passthrough path allowlists cmdlet names against the shape of a real
  cmdlet/function/alias, and every argument value is passed to the child process
  via an environment variable ($env:RTK_PS_ARG_<n>) instead of being
  interpolated into the -Command string.
• Registers a per-cmdlet hook rewrite pattern in src/discover/rules.rs (short
  aliases that collide with existing rules like ls/cat/ps/grep are
  deliberately not registered), and adds force_tee_hint/force_tee_tail_hint
  truncation recovery to every capped list.

Test plan

• cargo fmt --all && cargo clippy --all-targets && cargo test — all green (2442 passed)
• Manual testing: verified rtk powershell <Cmdlet> output against real PowerShell 5.1, and confirmed the hook rewrite (Get-Process → rtk powershell Get-Process) works without colliding with existing ls/cat/ps/grep rules

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