Harden contract + simplify scoring: trust active flag

[LandynDev]

Summary

• Add vote_deactivate validator-consensus method to the contract, gated on collateral < min_collateral — dormant escape hatch for the rare min-raise case, no permanent storage bloat.
• Block self-deactivate() while mid-swap or reserved so miners can't dodge in-flight obligations.
• Short-circuit scoring to full recycle when the contract is halted (single RPC check at entry, RPC failure falls through to normal scoring).
• Delete per-block collateral tracking from event_watcher.py/scoring.py — the contract's active flag is now authoritative.
• Delete per-block config-event tracking; halt is evaluated once at scoring entry.

Result: crown_holders_at_instant collapses to active ∧ rewardable ∧ ¬busy ∧ rate > 0. Validator state tracks only the active set, busy deltas, and swap outcomes.

Commit chain

1. Add vote_deactivate validator-consensus escape hatch
2. Block miner deactivation while mid-swap or reserved
3. Short-circuit scoring to full recycle when contract is halted
4. Drop collateral tracking from scoring; trust active flag
5. Drop config-event tracking; halt checked at scoring entry

Plan: plans/scoring-simplification-and-contract-hardening.md

Escape-hatch operational flow

If the owner ever raises min_collateral, maintainers ship a one-shot remediation script that iterates metagraph hotkeys, reads active + collateral via contract, and calls vote_deactivate(miner) for each active-but-below-floor miner. Validators run the release, quorum forms, active flag re-syncs with reality. No ongoing cost in normal operation.

Test plan

• cd allways/smart-contracts/ink && cargo check — passes
• cd allways && python -m pytest -q — 279 passed
• ruff check && ruff format --check — clean
• Deploy to dev env, attempt alw miner deactivate while reserved → expect CurrentlyReserved
• set_halted(true) → next scoring window logs V1 scoring: halted, recycled full pool
• Full E2E suite against dev env: ./tests/run.sh --chains btc