CONTEXT
## Patch: numbered-list marker alignment

This patch adds a **Marker alignment** option for numbered-list paragraph effects.

Problem: in numbered lists with suffixes such as dots, markers like `1.`, `2.`, `10.`, `100.` do not always align as expected. This is especially visible when moving from single-digit to double-/triple-digit numbering.

The patch adds this control to numbered-list settings:

```
Marker alignment: Left / Center / Right / Suffix
```

It is available in (2 places):

```
Style Manager → Paragraph Styles → Paragraph Effects → Numbered List
Properties Palette → Text → Paragraph Effects → Numbered List
```

Default remains Left, so existing documents should keep the same layout unless changed by the user.

### Behaviour

```
Left    keeps the current/default marker positioning.
Center  centers the marker inside the marker area.
Right   right-aligns the full generated marker.
Suffix  aligns markers by the suffix/end part, useful for lists like 1., 10., 100.
```

This allows users to get cleaner alignment for numbered lists while keeping existing behaviour available.

Implementation summary:

```
- Adds a ParagraphStyle property for numbered-list marker alignment.
- Saves/loads it as NumerationAlignment.
- Wires it into the Style Manager and Properties Palette paragraph-effect UI.
- Updates numbered-list layout so generated markers are positioned inside the marker area according to the selected alignment.
```

The layout change is done in the generated numbered-list marker handling, not through normal tab stops, because Scribus list markers are paragraph effects rather than ordinary typed text.