Update SDK local evaluation for per-condition-set aggregation

[dmarticus]

Part of #46288

Context

SDKs with local evaluation need to support per-condition-set aggregation and mixed person + group property filters.

Requirements

1. Read aggregation_group_type_index from each condition set (not flag-level)
2. Evaluate group property filters against provided group_properties
3. Use correct hash key based on condition set's aggregation:
   • None / not set → hash distinct_id
   • 0-4 → hash the corresponding group key from groups

Affected SDKs

All SDKs with local evaluation support:

• posthog-node — posthog-js#3474
• posthog-python — #523
• posthog-ruby — #138
• posthog-go — #192
• posthog-php — #134
• posthog-dotnet — #188
• posthog-rs — #107

N/A

• posthog-java — N/A (no local evaluation support)
• posthog-elixir — N/A (no local evaluation support)

Example (Python)

def evaluate_flag(flag, distinct_id, person_properties, groups, group_properties):
    for condition_set in flag['filters']['groups']:
        if not matches_properties(condition_set['properties'], person_properties, group_properties):
            continue
            
        agg_index = condition_set.get('aggregation_group_type_index')
        if agg_index is None:
            hash_key = distinct_id
        else:
            group_type = get_group_type_name(agg_index)
            hash_key = groups.get(group_type, '')
            if not hash_key:
                continue  # Can't evaluate without group context
                
        if hash_value(hash_key, flag['key']) < condition_set.get('rollout_percentage', 100):
            return True
            
    return False

Notes

• SDKs already receive groups and group_properties in evaluation calls
• Main change is reading aggregation per condition set and applying group property filters

[haacked]

This is complete. Updated issue description with all the corresponding PRs.