## metadata_parser.resolve_channel_roles()


Resolve channel role assignments (`nucleus` / `cell`) from channel names.


Usage

``` python
metadata_parser.resolve_channel_roles(channel_data)
```


Resolution rules, in priority order:

1.  Suffix `_nucleus` (case-insensitive) → role `nucleus`.
2.  Suffix `_cell` (case-insensitive) → role `cell`.
3.  Name (lower-cased) in `NUCLEUS_ALIASES` → role `nucleus`.
4.  Name contains `"Tub"` (legacy) → role `cell`.
5.  Otherwise → no role (channel is a feature channel only).


## Parameters


`channel_data: dict[str, int]`  
Mapping of channel name → channel index. Names are preserved verbatim; this function does not mutate the input.


## Returns


`dict[str, str]`  
Mapping `{role: channel_name}` containing at most one entry per role.

Keys are a subset of `{"nucleus", "cell"}`.


## Raises


`ChannelAnnotationError`  
If no nucleus role can be resolved, or if two channels resolve to the same role.