Subject-Verb Agreement and Verb Tense Consistency

https://github.com/AppFlowy-IO/AppFlowy-Docs/blob/b058a9f9a63da5b2afa4b78f2bbb7c9401c5b9f4/essential-documentation/appflowy-plugins/kanban-board.md?plain=1#L28
### Inaccurate Sentence:
You may have only one stack that `represent` "doing" or a couple of stacks that further `breaks` down "doing".

### Accurate Sentence:
You may have only one stack that `represents` "doing" or a couple of stacks that further `break` it down.

### Issues Fixed:
1. **"represent"** → **"represents"**: Corrects the verb to agree with the singular subject **"stack."**
2. **"breaks"** → **"break"**: Maintains tense consistency and agrees with the plural subject **"stacks."**

Open essential-documentation/appflowy-plugins/kanban-board.md at line 28 and read the surrounding paragraph. Correct the two subject-verb agreement and tense-consistency errors shown in the issue; done when the sentence matches the accurate wording and reads naturally.

Written by the indexing model from the issue text.