docs: add UI screenshots and update documentation with interface details

[jplanckeel]

Description

• Add 13 new UI screenshots to docs/assets/screenshots/ covering all major interface sections (dashboard, timeline, streamline, calendar, overlaps, insights, catalog, architecture, compliance, locks, drifts, rpa, links)
• Update README.md with new "Interface" section showcasing each UI component with corresponding screenshots
• Reorganize README features section to highlight new UI capabilities (sidebar navigation, global search, quick actions, theme options)
• Update USER_GUIDE.md table of contents and navigation section to reflect new sidebar structure with four main sections (Operations, Services, Infrastructure, Resources)
• Add Playwright artifacts to .gitignore (playwright-report/, test-results/, .playwright-mcp/)
• Enhance feature descriptions with new capabilities (Architecture View, Compliance Tracking, Lock Management UI, Homer Integration, Global Search, Quick Actions)
• Improve documentation clarity and organization to better reflect current product interface

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules