## Why

The homepage currently reserves space for the Instagram module even when there are no Instagram items available, which wastes above-the-fold real estate and makes the page less relevant.

## What Changes

- When the Instagram feed dataset is empty, the homepage MUST omit the Instagram module entirely (not render an empty state block).
- The rest of the homepage modules MUST continue to render normally.

## Capabilities

### New Capabilities
- (none)

### Modified Capabilities
- `homepage-content-modules`: change the "no Instagram items available" behavior from rendering an empty state to hiding/omitting the Instagram module.

## Impact

- Affected UI: homepage module composition and layout.
- Likely code changes in the homepage renderer (e.g., `site/src/pages/index.astro`) and any Instagram module component(s).
- Tests/verification should cover: with Instagram items => module visible; without items => module omitted.

