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_shape_ledger.py

@@ -80,5 +80,5 @@ def test_classify_and_list_are_mounted_as_mcp_tools():
     from scribe.mcp.server import build_mcp_server
 
     mcp = build_mcp_server()
-    for name in ("classify_shapes", "list_shapes"):
+    for name in ("classify_shapes", "list_shapes", "refresh_pattern_coverage"):
         assert mcp._tool_manager.get_tool(name) is not None