Configure App Transport Security (ATS) Explicitly

## Priority: Low

Explicitly configure ATS in Info.plist to enforce HTTPS for all connections.

## Current State
Using default ATS settings

## Implementation

Add to Info.plist:
```xml
NSAppTransportSecurity

NSAllowsArbitraryLoads

NSAllowsLocalNetworking

```

## Benefits
- Enforces HTTPS for all connections
- Prevents accidental HTTP usage
- Explicit security policy
- Better compliance posture

## Files to Modify
- Arkavo/Arkavo/Info.plist

## Testing
- Verify HTTPS enforcement
- Confirm InnerCircle P2P still works with local networking exception

## References
Part of security audit findings

Open Arkavo/Arkavo/Info.plist and inspect the current App Transport Security settings. Add the specified HTTPS enforcement and local networking exception, then verify HTTPS enforcement and confirm that InnerCircle P2P still works with local networking enabled.

Written by the indexing model from the issue text.