Implement governance proposals + weighted signed voting API (bounty #50)

[createkr]

Summary

This PR implements governance proposals and voting end-to-end for bounty issue #50.

What was added

• Database schema for governance proposals and votes.
• API endpoints:
  • POST /governance/propose
  • GET /governance/proposals
  • POST /governance/vote
  • GET /governance/proposal/
• Proposal lifecycle handling with clear status:
  • Draft -> Active (7 days) -> Passed/Failed
• Proposal creation rule:
  • proposer wallet must hold more than 10 RTC
• Voting rules:
  • signed Ed25519 vote verification (aligned with existing wallet signature style)
  • voter must be an active miner from attestation/miners view
  • weighted voting: weight = wallet_balance_rtc * antiquity_multiplier
• Pass/fail determination:
  • proposal closes to passed when yes_weight > no_weight, else failed
• Lightweight web UI:
  • GET /governance/ui serving web/governance.html
  • view proposals and submit vote payload
• README updates:
  • governance rules and endpoint examples
• Tests:
  • new route and governance logic coverage in tests/test_governance_api.py

Files changed

• node/rustchain_v2_integrated_v2.2.1_rip200.py
• web/governance.html
• README.md
• tests/test_governance_api.py

Test commands and results

• python3 -m py_compile node/rustchain_v2_integrated_v2.2.1_rip200.py tests/test_governance_api.py
  • Result: success
• python3 -m pytest -q tests/test_governance_api.py
  • Result: 2 passed, 1 warning