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

nisse-dev/tests/test_control.py

@@ -142,7 +142,7 @@ def test_a_message_is_matched_as_stripped_but_recorded_as_sent(
     h.transport.receive("don", "approve", original="Nisse Dev: approve")
     assert h.state == AWAIT_MILESTONE_SIGNOFF
     recorded = [
-        e.event.text for e in h.store.read_events() if isinstance(e.event, UserMessage)
+        e.event.text for e in h.store.all_events() if isinstance(e.event, UserMessage)
     ]
     assert "Nisse Dev: approve" in recorded
     assert "approve" not in recorded
@@ -160,6 +160,7 @@ def test_status_reports_state_and_gate(h: Harness) -> None:
 class QuestionThenPlan:
     def plan(
         self,
+        transcript: object,
         gate: str,
         project: str,
         feedback: str | None = None,
@@ -192,6 +193,7 @@ class FailsOnce:
 
     def plan(
         self,
+        transcript: object,
         gate: str,
         project: str,
         feedback: str | None = None,