feat(ttp): E.3.8 R0054-R0058 intel cohort + mark step done

5 YAMLs for the intel-verdict cohort per Appendix B / A.10:
AbuseIPDB category mapping, GreyNoise classification, Feodo
Tracker hit, ThreatFox IOC type, aggregate-malicious bump-only.
IntelLifter (E.3.10) consumes by rule_id and tolerates absence
silently (null provider column → no tag).

R0058 is the meta bump-only rule — emits a single confidence=0.0
sentinel so it validates and surfaces in the catalogue, but the
repository's sub-0.3 drop ensures no fresh tag persists if the
fanout fires accidentally. test_intel_rules.py pins that
zero-confidence invariant.

Marks E.3.8 done in development/TTP_TAGGING.md with the cohort-
split summary.

rules/ttp/R0057.yaml

@@ -0,0 +1,23 @@
+rule_id: R0057
+rule_version: 1
+name: threatfox_ioc
+description: |
+  abuse.ch ThreatFox IOC type → ATT&CK technique mapping with
+  family attribution.
+applies_to:
+  - intel
+match:
+  kind: lifter:intel_threatfox
+  provider: threatfox
+emits:
+  - tactic: TA0011
+    technique_id: T1071
+    confidence: 0.8
+  - tactic: TA0042
+    technique_id: T1588
+    sub_technique_id: T1588.001
+    confidence: 0.8
+evidence_fields:
+  - ioc_type
+  - malware_family
+  - threat_type