Code Farm: per-plot auto-replant pause and crop-lock check; community sync and node work

Continuous Delivery could never be turned off once a crop was planted. Add a
one-shot per-plot "stop after harvest" flag (POST /game/plot/stop, Devii tool
game_plot_stop, game_plots.stop_after_harvest), cleared by the next plant,
autoreplant claim or Refactor. Autoreplant now also respects crop locks through
the shared _crop_lock predicate. Plan and measurements in happyplanting.md.

Also includes the pending community sync, node network and related work in the
tree; the full suite passed (4999) with all of it.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

tests/api/sync/comments.py

@@ -9,7 +9,7 @@ def seed_thread(client, admin, origin):
     sync_ok(client, admin, "posts", origin, [post_record("p1", "u1"), post_record("p2", "u1")])
 
 
-def test_unknown_references_are_rejected_with_specific_reasons(client, admin, origin):
+def test_unknown_references_are_deferred_with_specific_reasons(client, admin, origin):
     seed_thread(client, admin, origin)
     body = sync_ok(
         client, admin, "comments", origin,
@@ -20,6 +20,7 @@ def test_unknown_references_are_rejected_with_specific_reasons(client, admin, or
         ],
     )
     assert [r["reason"] for r in body["results"]] == ["unknown_author", "unknown_post", "unknown_parent"]
+    assert [r["status"] for r in body["results"]] == ["deferred", "deferred", "deferred"]
 
 
 def test_create_with_nested_reply_in_one_batch(client, admin, origin):