UI - TA Form - Share Structure

Very complex component.
Planning for a few devs to review and brainstorm a good way forward for making this a business layer component before defining the other tickets.

### Previous reqs from BTR

**Validation**
- includes validations for maximum number of share class (limited based on combined max number of child series)
- includes validation for maximum number of share series (limited based on max number of parent class)
- If parent class changes par value and currency, the par value of child series changes to match the parent
- Par value and currency of child series is read only

**Removal and Undo**
- Display warning when removing special rights from a parent class that has one or more series
- Undoing special rights removal on parent undoes the removal of the series

**When a series would trigger a date**
- If the user enters the transition filing already having an existing share class with special rights, then they can add a series to it and say the series has special rights. If they have not already added a date within this filing, then we would prompt for a date by showing the date pop-up.

### Rules and validations outlined in figma
https://www.figma.com/design/9Lp6kpwm6JyfQmBqvRdVJF/Transition-Application?node-id=13741-114347&t=ZdE6LYQ32e1ICzbf-1
https://www.figma.com/design/9Lp6kpwm6JyfQmBqvRdVJF/Transition-Application?node-id=13357-72978&t=ZdE6LYQ32e1ICzbf-1
https://www.figma.com/design/9Lp6kpwm6JyfQmBqvRdVJF/Transition-Application?node-id=12757-24521&t=ZdE6LYQ32e1ICzbf-1

Start by reviewing the three linked Figma designs and the previous BTR requirements for the TA Form share structure. The issue calls for developer review and brainstorming before the business-layer approach and follow-up tickets are defined; done means an agreed design and clearly scoped implementation tickets, not a specific code change.

Written by the indexing model from the issue text.