feat: ACT/ECT strategy, package restructure, draft -01/-02 prep

Strategic work for IETF submission of draft-nennemann-act-01 and
draft-nennemann-wimse-ect-02:

Package restructure:
- move ACT and ECT refimpls to workspace/packages/{act,ect}/
- ietf-act and ietf-ect distribution names (sibling packages)
- cross-spec interop test plan (INTEROP-TEST-PLAN.md)

ACT draft -01 revisions:
- rename 'par' claim to 'pred' (align with ECT)
- rename 'Agent Compact Token' to 'Agent Context Token' (semantic
  alignment with ECT family)
- add Applicability section (MCP, OpenAI, LangGraph, A2A, CrewAI)
- add DAG vs Linear Delegation Chains section (differentiator vs
  txn-tokens-for-agents actchain, Agentic JWT, AIP/IBCTs)
- add Related Work: AIP, SentinelAgent, Agentic JWT, txn-tokens-for-agents,
  HDP, SCITT-AI-agent-execution
- pin SCITT arch to -22, note AUTH48 status

Outreach drafts:
- Emirdag liaison email (SCITT-AI coordination)
- OAuth ML response on txn-tokens-for-agents-06

Strategy document:
- STRATEGY.md with phased action plan, risk register, timeline

Submodule:
- update workspace/drafts/ietf-wimse-ect pointer to -02 commit

workspace/packages/act/tests/test_ledger.py

@@ -0,0 +1,84 @@
+"""Tests for act.ledger module."""
+
+import pytest
+
+from act.errors import ACTLedgerImmutabilityError
+from act.ledger import ACTLedger
+from act.token import ACTRecord, Capability, TaskClaim
+
+
+def make_record(jti, wid=None):
+    return ACTRecord(
+        alg="EdDSA", kid="k", iss="a", sub="b", aud="b",
+        iat=1772064000, exp=1772064900,
+        jti=jti, wid=wid,
+        task=TaskClaim(purpose="t"),
+        cap=[Capability(action="do.thing")],
+        exec_act="do.thing", pred=[], exec_ts=1772064100,
+        status="completed",
+    )
+
+
+class TestACTLedger:
+    def test_append_and_get(self):
+        ledger = ACTLedger()
+        r = make_record("jti-1")
+        seq = ledger.append(r)
+        assert seq == 0
+        assert ledger.get("jti-1") is r
+
+    def test_sequential_ordering(self):
+        ledger = ACTLedger()
+        for i in range(5):
+            seq = ledger.append(make_record(f"jti-{i}"))
+            assert seq == i
+
+    def test_duplicate_rejected(self):
+        ledger = ACTLedger()
+        ledger.append(make_record("jti-1"))
+        with pytest.raises(ACTLedgerImmutabilityError):
+            ledger.append(make_record("jti-1"))
+
+    def test_get_missing(self):
+        ledger = ACTLedger()
+        assert ledger.get("missing") is None
+
+    def test_list_all(self):
+        ledger = ACTLedger()
+        ledger.append(make_record("a"))
+        ledger.append(make_record("b"))
+        records = ledger.list()
+        assert len(records) == 2
+
+    def test_list_by_wid(self):
+        ledger = ACTLedger()
+        ledger.append(make_record("a", wid="w1"))
+        ledger.append(make_record("b", wid="w2"))
+        ledger.append(make_record("c", wid="w1"))
+        assert len(ledger.list("w1")) == 2
+        assert len(ledger.list("w2")) == 1
+        assert len(ledger.list("w3")) == 0
+
+    def test_verify_integrity_empty(self):
+        ledger = ACTLedger()
+        assert ledger.verify_integrity() is True
+
+    def test_verify_integrity_with_records(self):
+        ledger = ACTLedger()
+        for i in range(10):
+            ledger.append(make_record(f"jti-{i}"))
+        assert ledger.verify_integrity() is True
+
+    def test_verify_integrity_tampered(self):
+        ledger = ACTLedger()
+        ledger.append(make_record("jti-1"))
+        ledger.append(make_record("jti-2"))
+        # Tamper with chain hash
+        ledger._chain_hashes[0] = b"\x00" * 32
+        assert ledger.verify_integrity() is False
+
+    def test_len(self):
+        ledger = ACTLedger()
+        assert len(ledger) == 0
+        ledger.append(make_record("a"))
+        assert len(ledger) == 1