Built-in enrichment presets cannot be selected consistently from the local CLI

### Bug

The 3.4.0 local CLI cannot enable the documented enrichment presets through an ordinary config.

1. `picture_classification_preset: document_figure_classifier_v2` raises `Unknown picture classification preset`, although `DoclingConverterManagerConfig.default_picture_classification_preset` uses that value.
2. `picture_description_preset: granite_vision` raises that only `default` is allowed. The local CLI gives no way to set `allowed_picture_description_presets`.
3. `code_formula_preset: default` resolves through `default_code_formula_preset="default"`, then Docling raises because the available CodeFormula presets are only `codeformulav2` and `granite_docling`.
4. `code_formula_preset: codeformulav2` is rejected by Jobkit because the local CLI gives no way to add it to `allowed_code_formula_presets`.
5. `vlm_pipeline_preset: granite_docling` is rejected because the manager registers the configured default only under the key `default`; using `default` works.

A small embedding wrapper works after constructing `DoclingConverterManagerConfig` with:

```python
default_picture_description_preset="granite_vision"
allowed_picture_description_presets=["smolvlm", "granite_vision"]
default_code_formula_preset="codeformulav2"
allowed_code_formula_presets=["codeformulav2", "granite_docling"]
```

### Expected

The local CLI should accept built-in Docling preset IDs, and every configured default should resolve to a real Docling preset. The sample/config documentation should say when callers must use the alias `default` rather than the underlying preset ID.

Tested with `docling-jobkit==3.4.0` and Docling 2.121.0 on macOS arm64.

Start by tracing how the local CLI builds DoclingConverterManagerConfig and how Jobkit validates the five preset settings. Compare those paths with the working embedding-wrapper configuration described in the issue, then review the sample/config documentation. Done means built-in preset IDs and configured defaults resolve consistently, with the required `default` alias documented.

Written by the indexing model from the issue text.