Fix DHT synchronization workarounds in capability-based sharing

[Soushi888]

Overview

The capability-based private data sharing system (capability_based_sharing.rs) contains two temporary test workarounds for DHT synchronization issues that need to be resolved for production reliability.

Problem

Capability metadata link discovery fails intermittently during cross-agent operations, causing:

1. get_private_data_with_capability() to fall back to test workaround (line ~296)
2. revoke_private_data_access() to use RevokedGrantMarker entries instead of proper link deletion verification (line ~440)

Both locations are marked with:

// TEMPORARY TEST WORKAROUND
// TODO: Fix DHT synchronization issues with capability link discovery

Expected Behavior

• Capability metadata links (AgentToCapabilityMetadata) should be reliably discoverable across agents after dhtSync
• Grant revocation should verify through link deletion, not marker entries

Files

• dnas/nondominium/zomes/coordinator/zome_person/src/capability_based_sharing.rs (lines ~296, ~440)

Acceptance Criteria

• Remove both temporary test workarounds
• Capability metadata discovery works reliably across agents
• Grant revocation verification works without RevokedGrantMarker (or document why markers are the correct pattern)
• All existing capability sharing tests continue to pass

Related

• Completed in Implement Enhanced Private Data Sharing System #27: Core capability-based sharing system