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/ect/tests/test_ledger_extra.py

@@ -0,0 +1,38 @@
+"""Additional tests for ledger module."""
+
+import time
+
+import pytest
+
+from ect import Payload, MemoryLedger, ErrTaskIDExists
+
+
+def test_ledger_append_and_get():
+    m = MemoryLedger()
+    p = Payload(iss="i", aud=["a"], iat=1, exp=2, jti="j1", exec_act="act", pred=[])
+    seq = m.append("jws1", p)
+    assert seq == 1
+    assert m.get_by_tid("j1").jti == "j1"
+
+
+def test_ledger_err_task_id_exists():
+    m = MemoryLedger()
+    p = Payload(iss="i", aud=["a"], iat=1, exp=2, jti="j-dup", exec_act="e", pred=[])
+    m.append("jws1", p)
+    with pytest.raises(ErrTaskIDExists):
+        m.append("jws2", p)
+
+
+def test_ledger_contains_wid():
+    m = MemoryLedger()
+    p = Payload(iss="i", aud=["a"], iat=1, exp=2, jti="j1", exec_act="e", pred=[], wid="wf1")
+    m.append("jws", p)
+    assert m.contains("j1", "") is True
+    assert m.contains("j1", "wf1") is True
+    assert m.contains("j1", "wf2") is False
+
+
+def test_ledger_append_none():
+    m = MemoryLedger()
+    seq = m.append("jws", None)
+    assert seq == 0