In PowerPoint, Aligned equations in equation editor don't support line-by-line animation with Appear effect

## Description:

When creating aligned multiline equations in PowerPoint's equation editor (using `\eqnarray` or Shift+Enter with "Align at character"), the resulting equation object cannot be animated to reveal line-by-line using the Appear animation, unlike bulleted lists which support this functionality natively.

## Current Behavior:

- Aligned equations created with the equation editor render as a single object
- Applying the Appear animation reveals the entire equation block at once
- No option exists to animate individual lines of the aligned equation sequentially

## Desired Behavior:

Aligned equations should support line-by-line animation with the Appear effect (and other relevant animations), similar to how bulleted lists can be animated item-by-item. This would allow presenters to progressively reveal steps in mathematical computations.

## Impact:

### For Authors:
- Forces workaround of placing each equation line in separate textboxes and manually aligning them, which is time-consuming and error-prone
- Breaks the semantic structure of multi-step equations

### For Accessibility:
- Multiple separate textboxes may be harder for screen reader users to follow compared to a single structured equation object
- Loss of mathematical context when equations are split across disconnected objects

## Use Case:

This feature would be particularly useful for educational presentations where showing step-by-step mathematical derivations or computations helps students follow the logical progression of problem-solving.

## Workarounds (unsatisfactory):

1. Split each line into separate textboxes and manually align - labor intensive and breaks equation structure
2. Show entire computation at once - loses pedagogical value of progressive revelation

## Request:

Please add support for animating individual lines within aligned equation objects, similar to the existing functionality for bulleted lists.

No repository files, tests, or entry points are identified. Start by determining whether this project can affect PowerPoint's equation-editor animation behavior and by researching how aligned equations are represented; done means individual aligned lines can receive sequential Appear animations without splitting them into separate textboxes.

Written by the indexing model from the issue text.