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

docs/Development-Plan.md

@@ -99,7 +99,7 @@ test Matrix room, a budget-capped LiteLLM key; configuration in `~/nisse-e2e/`.
   section table this plan carried for the purpose.
 - Acceptance: `grep` finds no reference to the old spec or its section numbers.
 
-**M0.2 A bring-up script.** *Pre-approved.*
+**M0.2 A bring-up script.** *Pre-approved.* **Done.**
 - `scripts/bringup.sh`: set aside the previous run's state, workspace and log;
   export the ref under test; start the agent as a systemd unit, so it outlives the
   shell that started it; collect the log and a readable transcript
@@ -115,7 +115,7 @@ These fix problems found in the live runs that **survive the loop change.** Issu
 that only exist because of `control.py`'s state machine (#61, #79, #81) are folded
 into Phase 2's design instead of being fixed twice.
 
-**M1.1 Work items in the state store.** *Needs discussion* (schema).
+**M1.1 Work items in the state store.** *Needs discussion* (schema). **Done.**
 - A work-items table with an active pointer (L1); every canonical event carries its
   work item and its actor (L7). A migration for existing stores.
 - Acceptance: two work items back to back keep separate state and events; a