control whether Harper persists the global boot pointer

### Feature Summary

Investigate and implement a way to control whether Harper persists the global boot pointer (hdb_boot_properties.file) to the home directory. This is currently a hidden default behavior that can cause issues during integration testing or when running multiple instances. The goal is to make this behavior configurable or pluggable to allow for isolated runs without side effects on the machine's global state.

### Problem This Solves

integration testing brought this up, but we patched it over in that repo. There may be other cases where this would be helpful.

### Proposed Solution

env?

### User Stories

_No response_

### Alternatives Considered

_No response_

### Priority/Impact

None

### Examples or References

_No response_

### Additional Context

_No response_

### Are you planning to fix this issue?

No, just reporting the issue

### First-time contributor support

- [ ] I'm new to contributing and would appreciate guidance on the process
- [ ] I'd like help understanding the project structure
- [ ] I need assistance with setting up the development environment
- [ ] I'm comfortable contributing, but new to this project specifically