fix(powershell): ensure UTF-8 templates are written without BOM

[Nimraakram22]

Description
This PR fixes an issue where PowerShell 5.1 (default on Windows) writes files like CLAUDE.md with a UTF-8 Byte Order Mark (BOM). This invisible prefix causes parsing errors in modern tools like Claude Code and other Unix-style CLI utilities.

Changes
Stripped BOM from existing templates: Found and removed the BOM from all .md files in the templates/ and presets/ directories.

Hardened PowerShell logic: Replaced Copy-Item with a .NET based write method ([System.IO.File]::WriteAllText) in setup-plan.ps1 and create-new-feature.ps1 to force "UTF-8 No BOM" output, regardless of the source template's encoding.

Verification
Verified using the file command in MINGW64 to ensure output files now show as UTF-8 Unicode text instead of UTF-8 Unicode (with BOM) text.

[Copilot]

Pull request overview

This PR updates the PowerShell feature/setup scripts to ensure generated markdown files are written as UTF-8 without BOM (avoiding BOM-related parsing issues in Unix-style tooling).

Changes:

• Replaced Copy-Item template copying with a read + [System.IO.File]::WriteAllText(...) flow to force UTF-8 no BOM output.
• Applied the same UTF-8 no BOM write approach in both setup-plan.ps1 and create-new-feature.ps1.

Show a summary per file

File	Description
scripts/powershell/setup-plan.ps1	Writes plan.md from the template using UTF-8 no BOM instead of Copy-Item.
scripts/powershell/create-new-feature.ps1	Writes spec.md from the template using UTF-8 no BOM instead of Copy-Item.

Copilot's findings

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Comments suppressed due to low confidence (2)

scripts/powershell/setup-plan.ps1:39

• Variable $Utf8NoBom is PascalCase while other local variables in this file are lower camelCase (e.g., $paths, $template, $content). Consider renaming to match the local variable naming convention (e.g., $utf8NoBom).

    $Utf8NoBom = New-Object System.Text.UTF8Encoding($false)

scripts/powershell/create-new-feature.ps1:355

• Local variables in this script use lower camelCase (e.g., $featureDesc, $branchName), but $Utf8NoBom is PascalCase. Consider renaming to match the file's convention (e.g., $utf8NoBom).

            $Utf8NoBom = New-Object System.Text.UTF8Encoding($false)

• Files reviewed: 2/2 changed files
• Comments generated: 3

[Copilot]

On Windows PowerShell 5.1, Get-Content without -Encoding will treat UTF-8 without BOM as the system ANSI code page, which can corrupt non-ASCII characters in templates. Since you're normalizing output to UTF-8 no BOM, please also read the template using an explicit UTF-8 encoding (e.g., Get-Content -Raw -Encoding UTF8 or .NET ReadAllText).

This issue also appears on line 355 of the same file.

Suggested change

	# Read the template content and write it to the spec file with UTF-8 encoding without BOM
	$content = Get-Content -Raw -Path $template
	# Read the template content as UTF-8 and write it to the spec file with UTF-8 encoding without BOM
	$content = Get-Content -Raw -Encoding UTF8 -Path $template

[Copilot]

On Windows PowerShell 5.1, Get-Content without -Encoding will treat UTF-8 without BOM as the system ANSI code page, which can corrupt non-ASCII characters in templates (especially now that templates are expected to be UTF-8 no BOM). Read with an explicit UTF-8 encoding (e.g., Get-Content -Raw -Encoding UTF8 or a .NET ReadAllText overload) before writing.

This issue also appears on line 39 of the same file.

Suggested change

	# Read the template content and write it to the implementation plan file with UTF-8 encoding without BOM
	$content = Get-Content -Raw -Path $template
	$Utf8NoBom = New-Object System.Text.UTF8Encoding($false)
	[System.IO.File]::WriteAllText($paths.IMPL_PLAN, $content, $Utf8NoBom)
	# Read the template content as UTF-8 and write it to the implementation plan file with UTF-8 encoding without BOM
	$content = Get-Content -Raw -Encoding UTF8 -Path $template
	$Utf8NoBom = New-Object System.Text.UTF8Encoding($false)
	[System.IO.File]::WriteAllText($paths.IMPL_PLAN, $content, $Utf8NoBom)

[Copilot]

[System.IO.File]::WriteAllText(...) is not indented like the rest of the if block, which makes the block harder to read and looks accidental. Please align its indentation with the surrounding statements.

Suggested change

	[System.IO.File]::WriteAllText($paths.IMPL_PLAN, $content, $Utf8NoBom)
	[System.IO.File]::WriteAllText($paths.IMPL_PLAN, $content, $Utf8NoBom)

[mnriem]

Please address Copilot feedback. If not appicable, please explain why