fix(skills): omit column widths by default in generated grid code

[onlyexeption]

Closes #1696

Description

Motivation / Context

Type of Change (check all that apply):

• Bug fix
• New functionality
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring (no functional changes)
• Documentation
• Demos
• CI/CD
• Tests
• Changelog
• Skills/Agents

Component(s) / Area(s) Affected:

How Has This Been Tested?

• Unit tests
• Manual testing
• Automated e2e tests

Test Configuration:

• Angular version:
• Browser(s):
• OS:

Screenshots / Recordings

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them
• Accessibility (ARIA, keyboard navigation, focus management) has been verified

[Copilot]

Pull request overview

Updates the Ignite UI Angular grid skills reference docs to guide generated grid code toward omitting per-column width by default, allowing columns to auto-distribute available space unless the user explicitly requests fixed sizing (addresses the issue about unnecessary default column widths in generated code).

Changes:

• Clarifies the width input description for igx-grid-lite-column to recommend omitting it by default.
• Adds explicit “omit width by default” guidance to the key rules in both standard grid (<igx-column>) and Grid Lite (<igx-grid-lite-column>) reference docs.
• Adds sizing guidance explaining why fixed pixel widths can lead to unused/empty space and when width should be set.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
skills/igniteui-angular-grids/references/types.md	Updates Grid Lite column width guidance and adds a key rule to omit width by default for generated Grid Lite columns.
skills/igniteui-angular-grids/references/structure.md	Adds a key rule instructing generated <igx-column> elements to omit width unless explicitly requested.
skills/igniteui-angular-grids/references/sizing.md	Adds a sizing rule explaining the effects of omitting width vs. using fixed pixel widths and when to set width.