MissingModelsWarning has hardcoded download sources

## Recommendation

### 🔧 FINISH: Read allowed sources from server API

`allowedSources`, `allowedSuffixes`, and `whiteListedUrls` are hardcoded in the component instead of coming from the server.

## What Was Found

- `src/components/dialog/content/MissingModelsWarning.vue:45-58` — `// TODO: Read this from server internal API rather than hardcoding here`

## Context

Custom installations should be able to configure their own download source restrictions via the server API.

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**Category:** Half-Implemented | **Confidence:** HIGH | **Tools:** Semantic analysis
_Filed by audit-code skill_

Part of #11022

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-11051-MissingModelsWarning-has-hardcoded-download-sources-33e6d73d365081118ea9fb3c7fc90ac8) by [Unito](https://www.unito.io)

Start at src/components/dialog/content/MissingModelsWarning.vue:45-58 and inspect the server API contract for allowedSources, allowedSuffixes, and whiteListedUrls. Confirm how custom installations expose these restrictions. Done means the component uses the server-provided values instead of hardcoded sources and honors configured download restrictions.

Written by the indexing model from the issue text.