Add GitHub badges to README

[Exohayvan]

Added GitHub badges for code size, open/closed issues, and pull requests to README.

Objective

What changed

Validation

• git diff --check
• PYTHONDONTWRITEBYTECODE=1 python3 scripts/full_test.py --mode fast --base origin/main --keep-going

AetherMesh alignment

• Makes the local prototype more runnable, measurable, validated, or easier to extend.
• Preserves the AER / REVA / AEF direction in docs/persistent-goal.md and docs/architecture.md.
• Avoids tokenomics, payout logic, dashboard-first work, or unsupported decentralization claims.
• Keeps the change small enough to review safely.

Safety notes

Follow-ups