Add September sprint highlights blog update

[billjohnc]

Why

We needed a new sprint-highlights post for the 1 September 2026 community call, aligned to the existing "Sprint Highlights: Product, Platform & Engineering Improvements" series style.

What changed

This PR adds a new blog entry and a dedicated cover illustration for that post.

1. Added content/blog/community-call-5-september-2026.md with sprint-highlights format, including:

• Series-aligned title and excerpt
• Structured sections for documentation, pharmacy workflow, observability/tooling, sandbox support, AI Vision updates, and encounter flow simplification
• Linked references to all discussed PRs and resources
• featured: true metadata

2. Added public/blog/covers/community-call-5-september-2026.svg as the post-specific cover image, with text aligned to the sprint-highlights series naming.

Notes for review

The content intentionally follows the same narrative structure and tone as the earlier sprint-highlights blog in this series, rather than a meeting-notes style call summary.

[gauritejusa]

• Would be nice to mention pharmacy user friendliness wrt the new UI/UX updates
• React doctor clarity
• What is AI vision and its usability and powerfulness

[billjohnc]

Thanks for the feedback! I've addressed all three points with the latest commit:

1. Pharmacy user friendliness wrt UI/UX updates: Updated the pharmacy section to explicitly mention the UI/UX refinements - specifically that we streamlined the billing interface to reduce clicks, consolidate information density, and simplify navigation paths for pharmacy staff. This provides more context on what "user friendliness" improvements actually means in practice.

2. React Doctor clarity: Expanded the description to highlight specific capabilities developers can expect - identifying bottlenecks, component inefficiencies, and architectural debt patterns across React applications. This gives readers a clearer sense of its value and power for diagnosing performance issues.

3. AI Vision usability and powerfulness: Added language that directly addresses both dimensions - "The system is powerful for automating image analysis tasks while remaining usable for clinicians with varying technical backgrounds." Also expanded the closing sentence to emphasize how the UI enhancements enable frontline teams to leverage AI insights more effectively.

The changes are now live on the branch. Let me know if you'd like any adjustments!