Add copilot PowerShell wrapper that pre-approves safe file writes

[Copilot]

Every file create/edit in Copilot CLI triggers a manual accept prompt, even in trusted, git-tracked repos where git diff/git restore already provide a safety net. This adds a copilot PowerShell wrapper that pre-approves file writes only, leaving shell and MCP tools gated.

Changes

• Invoke-Copilot function (Public/Copilot.ps1): resolves the real copilot executable via Get-Command -CommandType Application (never itself, avoiding alias recursion) and invokes it with --allow-tool=<list> prepended.
  • Defaults to write (file create/edit only).
  • Allow-list is configurable via $env:COPILOT_ALLOW_TOOLS, so it can be widened (e.g. read-only git status/git diff) or narrowed without editing the function.
  • -Raw switch bypasses pre-approval entirely as an escape hatch.
  • Throws a clear error if copilot isn't found on PATH.
• Alias wiring: copilot alias added in aliases.ps1 pointing to Invoke-Copilot; function registered in DotfilesHelpers.psd1 FunctionsToExport, matching the existing Connect-CopilotSsh pattern.
• Docs: new "Pre-approving safe file writes (PowerShell)" section in docs/copilot-cli.md, clarifying this is independent from the existing bash/zsh/fish 1Password shell-plugin wrapper.
• Tests: new Pester suite validates default/overridden allow-tool values, argument forwarding, -Raw bypass, and missing-CLI error handling using a PATH-stubbed copilot executable.

copilot                 # runs with --allow-tool=write pre-approved
copilot -Raw             # unwrapped CLI, every tool call prompts
$env:COPILOT_ALLOW_TOOLS = 'write,shell(git status),shell(git diff)'
copilot                  # widened allow-list

• Fixes Add a copilot PowerShell wrapper that pre-approves safe file writes (--allow-tool='write') #637