Update community dashboard metrics

[JoaquinBN]

Summary

• route /community to the shared dashboard with community-specific sections
• count community members from visible users with accepted community contributions
• show community contributor, podium, recent contribution, highlight, and CTA data without referral-point metrics

Verification

• npm run build
• env/bin/python -m py_compile leaderboard/views.py leaderboard/tests/test_stats.py

Note: the focused Django test is blocked in this workspace by an existing data migration that expects albert@genlayer.foundation in the test database.