The queue: parking, the operator's order, blocked items (M2.2)

Several work items on the new loop (L1, D4):
- Switching parks the item on the workspace: its work is committed and its
  branch pushed; resuming checks the item's branch back out. Branches of
  open items are never set aside by a fresh workspace.
- Next item: the operator's "do #N next" first, otherwise the oldest.
- Issues with open Gitea dependencies are blocked until they close, checked
  at intake and on every round; status shows blocked items and the line.

Tests: queue unit tests, the property walk over several issues with
dependencies and a new parked_work_safe property (it catches parking
disabled), and an end-to-end test with two issues where B depends on A.

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

docs/Development-Plan.md

@@ -23,7 +23,7 @@ Only `nisse-dev` has real code; `nisse-core` and `nisse-ops` are placeholders.
 
 | Section | Status | Notes |
 |---|---|---|
-| **L1** Work model | partial | Work items table with an active pointer (M1.1); no issue intake, queue, parking or blocked items |
+| **L1** Work model | mostly done | Work items with an active pointer (M1.1); issue intake (M2.1); queue, parking and blocked items (M2.2) on the new loop; no grace period yet |
 | **L2** Agent loop | partial | `control.py`, a fixed state machine with no-stranding, `stop`, `abandon`. Replaced by the new loop (Phase 2) |
 | **L3** Authority | partial | Revision binding and arrival stamping (`gates.py`); scope is still plan approval, not the issue and its conversation |
 | **L4** Classifier | none | |
@@ -144,9 +144,15 @@ later one widens it and extends the end-to-end test (M1.6) to cover it.
 - Acceptance: the end-to-end test runs that path on the new loop, plus a crash
   mid-publish; then a first manual live run.
 
-**M2.2 The queue.** *Pre-approved.* Several items: states, park-and-switch with
-branches pushed, next-item order, blocked items from Gitea dependencies, a closed
-PR handled (L1, D4). End-to-end: two issues and a dependency.
+**M2.2 The queue.** *Pre-approved.* **Done** (this PR). Several items: states,
+park-and-switch with branches pushed, next-item order, blocked items from Gitea
+dependencies, a closed PR handled (L1, D4). End-to-end: two issues and a dependency.
+- Switching happens as soon as the active item waits; the grace period (§6, L1)
+  is left until a watching operator misses it. Order is "do #N next"; priority
+  labels and driver-chosen order wait for a need.
+- The property walk covers several issues, dependencies and the operator's order,
+  and checks that parked work is never lost (every file an open item wrote is on
+  the workspace or in the forge).
 
 **M2.3 Threads and labels.** *Pre-approved.* Routing by thread, ambiguous commands
 asked about (L5); `bug` grace periods, `discuss`, `design`; questions and