Asset browser category derivation from tags is brittle and shows configs in All Models

## Summary

The asset browser currently derives model type/category directly from raw asset tags in a way that is too brittle.

This creates two user-visible problems:

- category/type handling becomes sensitive to tag layout instead of model semantics
- config assets can appear in `All Models`, which pollutes the main model browsing experience

## Current behavior

The asset browser currently derives type/category from non-`models` tags and uses that information for badges/navigation/filtering.

This causes problems such as:

- assets with semantically equivalent model tags but different tag layout/order not being treated consistently
- categories being derived from raw tag structure rather than from a stable model-type interpretation
- assets tagged like `['models', 'configs']` appearing in `All Models`, even though they are config files rather than actual models

## Expected behavior

The asset browser should:

- only infer a model type when the asset is actually a model asset
- derive category/type from a stable model-type interpretation, not from brittle raw-tag assumptions
- keep config assets out of `All Models` while still allowing them to be discovered in an appropriate category if needed

## Minimal repro

1. Have a config asset tagged as `['models', 'configs']`
2. Open the asset browser and select `All Models`
3. Observe that the config file appears alongside actual model assets

A related issue is that model category/type derivation is currently tied too closely to raw tag structure, which makes behavior brittle when tags are not laid out exactly as the UI expects.

## Why this matters

`All Models` should primarily surface real model assets. Mixing config files into that view makes browsing noisier, and brittle tag interpretation makes category behavior harder to reason about.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-10608-Asset-browser-category-derivation-from-tags-is-brittle-and-shows-configs-in-All-Model-3306d73d3650812c88f8f62685c18b7b) by [Unito](https://www.unito.io)

Start at the asset browser entry point, focusing on category/type derivation and the All Models filtering described in the issue. Trace how raw tags such as ['models', 'configs'] are interpreted, then verify that real model assets retain stable categories while config assets are excluded from All Models and remain discoverable in an appropriate category.

Written by the indexing model from the issue text.