feat(docs): add extension collections overview and integrate into getting started flow

[PratikWayase]

Pull Request

Description

This PR improves the extension installation experience by introducing a collections overview page and integrating it into the Getting Started documentation flow.

The goal is to help users quickly understand available HVE extension bundles and choose the appropriate workflow.

Changes Included

• Added a new Extension Collections documentation page
• Linked the collections page from the installation guide
• Referenced collections in the Getting Started flow
• Added a collections card in the documentation hub
• Updated the extension README template to link to the collections overview

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Related Issue(s)

Closes #859

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Type of Change

Code & Documentation

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to change)
• Documentation update

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Testing

The documentation changes were validated by:

• Running markdown lint checks
• Running frontmatter validation
• Verifying internal documentation links
• Reviewing the documentation site preview to ensure links render correctly

Commands Executed

npm run lint:all

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Checklist

Required Checks

• Documentation is updated (if applicable)
• Files follow existing naming conventions
• Changes are backwards compatible (if applicable)
• Tests added for new functionality (not applicable)

Required Automated Checks

• Markdown linting: npm run lint:md
• Spell checking: npm run spell-check
• Frontmatter validation: npm run lint:frontmatter
• Skill structure validation: npm run validate:skills
• Link validation: npm run lint:md-links
• PowerShell analysis: npm run lint:ps
• Plugin freshness: npm run plugin:generate (not applicable)

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Security Considerations

• This PR does not contain any sensitive or NDA information
• Any new dependencies have been reviewed for security issues
• Security-related scripts follow the principle of least privilege

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Additional Notes

This change focuses on improving discoverability of extension collections and integrating them into the installation and Getting Started workflow, supporting the simplified extension install experience described in Issue #859.

[katriendg]

Thanks for putting this together, @PratikWayase! The collections overview page and cross-linking are a solid start. I have a few items to address before we can merge.

Unrelated changes — please remove

This PR includes a file that aren't part of #859 and should be submitted separately:

.github/workflows/weekly-security-maintenance.yml — Adding stale SHA issue auto-creation (64 new lines) is a workflow/security change with no connection to #859. This needs its own PR with appropriate review.

Missing items from the acceptance criteria in #859

The issue specifies several requirements that aren't addressed yet:

• Expandable or linked descriptions per collection — The table is a good start, but #859 asks for each collection to have an expandable description (or link) showing the specific agents and capabilities included. Currently it's just a flat table row.
• Maturity status indicators — Design Thinking should be marked Preview and Experimental should be marked Experimental, per the implementation notes in the issue.
• Homepage hero section CTA — The issue proposes an update to docs/docusaurus/src/pages/index.tsx for a hero section install CTA. This file wasn't touched.
• Hub card destination — The new hub card links directly to the marketplace, but the issue asks for a link to the collections overview page (or both marketplace and collections overview), so users can compare bundles before installing.

Code quality items

• VsCodeExtensionIcon formatting — The component has inconsistent quote styles (single vs double), irregular indentation, and spacing that doesn't match the existing icon components in the file. Please align with the style of DesignThinkingIcon and others already in Icons/index.tsx.
• SVG gradient bug — offset="100" on the last gradient stop should be offset="100%".
• collections.md frontmatter — The author field uses lowercase pratik wayase; please use proper casing.
• Missing trailing newline — collections.md is missing a final newline.
• Hardcoded artifact counts — The issue notes that counts should be verified against collections/*.collection.yml. Please double-check these are accurate as of the current main branch.

Summary

Please:

1. Remove the two unrelated file changes and submit them as separate PRs
2. Address the missing acceptance criteria items listed above
3. Fix the code quality items

Happy to re-review once these are addressed!