Put work items in the state store, and bind the log to them (M1.1)

Development Plan M1.1, as discussed.

- Schema v4: a work_items table (id, scope, title, status, outcome,
  position, data) and an agent row whose active_item points at one
  (NULL: idle). Canonical events and intents carry their work item, and
  events their actor. Older stores are refused with a clear message:
  there was no production data, so no migration (the mechanism stays).
- The log is reached through a Transcript bound to one work item and
  one actor: store.transcript(item, actor) reads only that item and
  writes with both. The planner, executor, delegation and expert desk
  get one per call from the orchestrator instead of holding the store,
  so a component can neither read another task's events (the planner
  read every earlier task's, #78) nor write without attribution.
  store.all_events() is kept for readers that span items (evaluation
  capture, dumps). Intents are begun through the transcript or with
  work_item=, so each belongs to its item.
- The orchestrator opens a work item on 'use', closes it with its
  outcome (completed or abandoned), and carries what the operator said
  while idle into the new item as copies with their origin, so a task
  sent before 'use' is still planned from (D1). control.py keeps its
  state machine through get_state()/transition(), now over the active
  work item, until M2.6 retires it.
- nisse_dev.dump shows work items and each event's item and actor.

Tests: test_work_items.py (scoping, attribution, intent ownership,
restart, outcomes, carried messages, a second task never seeing the
first); the suites updated for the per-call transcript.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE

tests/integration/test_passthrough_live.py

@@ -24,7 +24,7 @@ pytestmark = pytest.mark.integration
 def store_with(tmp_path: Path, *events) -> StateStore:
     store = StateStore(tmp_path / "state.db", oplog=OpLog("nisse-dev", io.StringIO()))
     for event in events:
-        store.append_event(event)
+        store.transcript("t", "helper").append(event)
     return store
 
 
@@ -35,7 +35,7 @@ def test_passthrough_completes_a_plain_turn(
         tmp_path, UserMessage(text="Reply with exactly: pong", source="live")
     )
     result = passthrough.complete(
-        store.read_events(), None, live_model, system="Be terse."
+        store.transcript("t", "helper").read(), None, live_model, system="Be terse."
     )
     texts = [e.text for e in result if isinstance(e, AssistantText)]
     assert texts and "pong" in texts[0].lower()
@@ -53,7 +53,7 @@ def test_passthrough_round_trips_a_tool_call(
     )
     client = passthrough
     produced = client.complete(
-        store.read_events(),
+        store.transcript("t", "helper").read(),
         EXECUTOR_TOOLS,
         live_model,
         system="Use a tool. Do not answer in prose.",
@@ -64,11 +64,13 @@ def test_passthrough_round_trips_a_tool_call(
     # Feed the result back: the follow-up render must be accepted, which is
     # what proves tool_result placement is right for this vendor.
     for event in produced:
-        store.append_event(event)
-    store.append_event(
+        store.transcript("t", "helper").append(event)
+    store.transcript("t", "helper").append(
         ToolResult(call_id=calls[0].call_id, result="app.py\ntests/", success=True)
     )
-    follow_up = client.complete(store.read_events(), EXECUTOR_TOOLS, live_model)
+    follow_up = client.complete(
+        store.transcript("t", "helper").read(), EXECUTOR_TOOLS, live_model
+    )
     assert follow_up, "the vendor rejected or ignored the tool_result turn"