Pinning Fixed Width Columns

[hellovolcano]

Pull Request

🤨 Rationale

This PR adds support for pinning fixed-width table columns to the left side of the Nimble table, with primary support for icon-sized mapping columns.

Works toward addressing #848.

👩‍💻 Implementation

Added a sticky pinned column. When a column is pinned, it is the only thing that is sticky. Multiple fixed width columns can be pinned.

• Implemented pinned-column rendering/layout in the table so pinned columns are separated from scrollable columns, rendered as sticky, and sized from pixel widths.
• Updated row/group-row behavior so indentation is applied at the first non-pinned column and group rows account for pinned-column offset.
• Added table validation for pinned-column configuration (invalidPinnedColumnConfiguration) to catch pinned columns without a resolvable fixed width.
• Updated table update tracking so pinned state changes trigger required layout/focus recalculations.
• Updated Storybook mapping-column docs/examples to expose pinned property.
• Added angular and blazor wrappers

🧪 Testing

Added unit tests for pinned columns to table test spec
Added matrix tests to catch multiple combinations of table configuration
Manually verified:

• Pinned column appears correctly when grouping, multi-select, and hierarchy are enabled
• First non-pinned column has hierarchy indentation applied correctly
• Pinned column is the only sticky column

✅ Checklist

• I have updated the project documentation to reflect my changes or determined no changes are needed.

[jattasNI]

I ran out of time to do a full review today. Just pointing out a couple things I noticed when playing with storybook.

[mollykreis]

I also ran out of time to review this today, but an additional observation from looking at storybook is that I think the "Collapse All" button in the table header should be pinned so it stays aligned with the "collapse" button on each group row (or at least the rows with the outer-most level of grouping)

[rajsite]

@hellovolcano I wasn't able to complete a review today, I do expect to review Monday