Allow user to force the default implicit formatting to use AutoSize - #28018

Adds $PSStyle.AutoSizeDefaultFormatting to enable AutoSize for implicit table and wide formatting.

Changes:

• Adds the new $PSStyle setting.
• Applies it during default formatting.
• Adds formatting tests.

Suppressed comments (2)

src/System.Management.Automation/FormatAndOutput/common/PSStyle.cs:647

• The default PSStyle view is an explicit ListControl that enumerates the top-level settings (PowerShellCore_format_ps1xml.cs:2139-2212), but it has no entry for AutoSizeDefaultFormatting. As a result, $PSStyle and $PSStyle | Format-List hide this new user-facing setting; add it to the generated default formatter view.

        public bool AutoSizeDefaultFormatting { get; set; }

test/powershell/engine/Formatting/PSStyle.Tests.ps1:624

• The cleanup hard-codes $false instead of restoring the value present when the test started. Because PSStyle.Instance is process-wide and the surrounding tests save and restore settings (for example, lines 143-153), this can leak state to later tests and makes the test depend on an initially disabled feature. Save the original value, establish a false baseline before capturing $defaultOutput, and restore the original in finally.

            $PSStyle.AutoSizeDefaultFormatting = $false

• Files reviewed: 3/3 changed files
• Comments generated: 3
• Review effort level: Lite

Suppressed comments (2)

src/System.Management.Automation/FormatAndOutput/common/PSStyle.cs:647

• This adds a new public $PSStyle setting that users must discover and configure, while the PR checklist marks “User-facing changes” as Not Applicable. Please update the user-facing PSStyle documentation (or file the required documentation issue) and correct the checklist before merging.

        public bool AutoSizeDefaultFormatting { get; set; }

src/System.Management.Automation/FormatAndOutput/format-default/format-default.cs:33

• The no-default-view branch in FormatViewManager.Initialize() still calls SelectViewGeneratorFromProperties(..., null), so this parameters object is discarded for inferred views. As a result, $PSStyle.AutoSizeDefaultFormatting = $true has no effect for an untyped object that is inferred as a table (for example, a [pscustomobject] with four or fewer properties), even though the feature promises to autosize the chosen table/wide view. Preserve null for shape inference, then apply the autosize flag to the resulting Table/Wide generator, and add a regression case for this path.

                var parameters = new FormattingCommandLineParameters { autosize = true };
                ((InnerFormatShapeCommand)this.implementation).SetCommandLineParameters(parameters);

• Files reviewed: 5/5 changed files
• Comments generated: 0 new
• Review effort level: Lite