feat(alpha): complete hardening backlog

Complete the alpha-hardening Ralph task set, including tracker billing/accounting guards, validator fraud-audit primitives, wallet binding proof support, documentation runbooks, and updated tests.

Verification: .venv/bin/python -m compileall -q packages tests; .venv/bin/python -m pytest -q --tb=short (313 passed, 3 skipped, 1 failed: tests/test_mining_cli.py::test_legacy_start_without_port_uses_next_available_port because meshnet-node pid 1263451 is already listening on port 7000).

.scratch/alpha-hardening/issues/06-fraud-toploc-integration.md

@@ -1,4 +1,4 @@
-Status: ready-for-agent
+Status: done
 
 # 06 — FRAUD: TOPLOC integration (teacher-forced audit primitive)
 
@@ -29,11 +29,11 @@ Pin one canonical precision/quantization per model preset. Add `toploc` to valid
 
 ## Acceptance criteria
 
-- [ ] `toploc` dependency declared; `build_proofs_*` / `verify_proofs_*` wired
-- [ ] Validator re-runs claimed token sequence as prefill, not free generation
-- [ ] Model preset documents canonical dtype/quantization
-- [ ] README updated: 19× deterrence at 5% audit (research §1.1)
-- [ ] Tests with deterministic stub tensors (no GPU required in CI)
+- [x] `toploc` dependency declared; `build_proofs_*` / `verify_proofs_*` wired
+- [x] Validator re-runs claimed token sequence as prefill, not free generation
+- [x] Model preset documents canonical dtype/quantization
+- [x] README updated: 19× deterrence at 5% audit (research §1.1)
+- [x] Tests with deterministic stub tensors (no GPU required in CI)
 
 ## ADR links