feat(ledger): coverage self-seeds — enter_project background refresh + refresh_pattern_coverage tool + shape-accounting skill (#2802, milestone 294)

The UI Refresh button must not be the only seed path (operator directive,
hit live: the P7 backfill stalled waiting for a click). Three parts:

- enter_project fire-and-forgets refresh_if_stale on the project OWNER —
  absent or day-old readouts recompute in the background (same spawn the
  webhook path uses), the enter stays fast, forge-less owners exit quietly
  (rule #115 baseline), and an in-flight guard keeps concurrent enters from
  fetching the same tarball N times.
- refresh_pattern_coverage(project_id): the synchronous agent-facing form —
  write-gated, owner-keyring resolution, and ValueError messages that name
  the fix (add a connection / bind_repo) instead of measuring nothing
  silently.
- plugin 0.1.33 ships the shape-accounting skill: the five statuses, the
  seed/todo/judge loop, and the derive-first rule, triggered by the
  coverage line or any proved code-to-canon relationship.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_mcp_tool_projects.py

@@ -40,6 +40,15 @@ def _no_coverage():
         yield
 
 
+@pytest.fixture(autouse=True)
+def _no_background_seed():
+    """enter_project now fire-and-forgets a coverage self-seed (#2802). These
+    are no-database unit tests, so the spawn is stubbed out; the firing shape
+    has its own test below."""
+    with patch("scribe.mcp.tools.projects.spawn") as mock:
+        yield mock
+
+
 @pytest.fixture(autouse=True)
 def _no_bootstrap():
     """With _no_systems stubbing an empty vocabulary, every test here reaches
@@ -319,6 +328,31 @@ async def test_enter_project_never_asks_bootstrap_once_a_vocabulary_exists(
         ))
         out = await enter_project(project_id=5)
     assert "systems_bootstrap" not in out
+
+
+@pytest.mark.asyncio
+async def test_enter_project_fires_the_coverage_seed_on_the_owner(
+    _no_background_seed,
+):
+    """The arrival self-seed (#2802): entering spawns refresh_if_stale on the
+    project OWNER's id with the cache read the enter already did — fire and
+    forget, so a missing ledger seeds itself without the UI button, and the
+    enter stays fast."""
+    import contextlib
+
+    project = _fake_project(id=5)
+    project.user_id = 42  # explicit: the OWNER, not the caller (ctx uid=7)
+    with contextlib.ExitStack() as stack:
+        for cm in _enter_project_stubs(project):
+            stack.enter_context(cm)
+        seed = stack.enter_context(patch(
+            "scribe.mcp.tools.projects.coverage_svc.refresh_if_stale",
+            MagicMock(return_value=object()),
+        ))
+        await enter_project(project_id=5)
+    seed.assert_called_once_with(42, 5, cached=None)
+    _no_background_seed.assert_called_once()
+    assert _no_background_seed.call_args.kwargs["site"] == "enter_project.coverage_seed"
     _no_bootstrap.assert_not_awaited()