feat: make start identities number u16

[pauldelucia]

Issue being fixed or feature implemented

Strategy start identities number was u8. We need more than 255.

What was done?

Change to u16.

How Has This Been Tested?

Platform TUI and cargo tests

Breaking Changes

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have added "!" to the title and described breaking changes in the corresponding section if my code contains any
• I have made corresponding changes to the documentation if needed

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone