[ci-maintainer] Import reference architectures fails daily: raster-embedded SVGs, rsvg-convert missing (fix PR #49 open)

## CI Issue

The daily `Import reference architectures` workflow fails at `npm run validate:architecture-assets` because two imported SVGs contain embedded raster image data:

```
[error] static/img/architectures/swisscom-cloud-native-telco/swisscom-cloud-native-telco-automation-architecture-overview.svg: contains embedded raster image data
[error] static/img/architectures/zeiss/solutionArchitecture.svg: contains embedded raster image data
```

`scripts/import-architectures.mjs` already handles this by shelling out to `rsvg-convert` to rasterize these SVGs to PNG — but the CI runner never installs it, so the script warns (`Could not convert raster-embedded SVG; consider installing rsvg-convert`) and validation then fails.

## Evidence

- Latest failing run: [31236125534](https://github.com/castrojo/endusers/actions/runs/31236125534) (2026-08-08T02:57, schedule)
- The workflow has no successful run on record (2/2 failures).

## Recommendation

Merge PR #49 (`ci: install librsvg2-bin for import-architectures workflow`, open since 2026-08-08, mergeable/clean) — it adds the one-line `apt install librsvg2-bin` step. This issue gives that PR a `Fixes #` target.

---
*Filed by ci-maintainer agent (ACMM L6 — full mode)*

Start with the daily Import reference architectures workflow and scripts/import-architectures.mjs, then reproduce npm run validate:architecture-assets. Done means the CI runner provides rsvg-convert and the two raster-embedded SVGs pass validation; PR #49 already proposes this fix.

Written by the indexing model from the issue text.