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>

src/scribe/mcp/tools/shapes.py

@@ -9,6 +9,7 @@ refresh; these tools only ever judge what the sync has seen.
 from __future__ import annotations
 
 from scribe.mcp._context import current_user_id
+from scribe.services import coverage as coverage_svc
 from scribe.services import shape_ledger as shape_ledger_svc
 
 
@@ -90,6 +91,34 @@ async def list_shapes(
     return {"shapes": [r.to_dict() for r in rows], "total": total}
 
 
+async def refresh_pattern_coverage(project_id: int) -> dict:
+    """Seed or refresh the project's shape ledger NOW, and return the readout.
+
+    The synchronous form of the arrival-moment background seed (#2802):
+    downloads the bound repos through the OWNER's forge connections, upserts
+    every extracted shape into the ledger (new shapes arrive `unclassified`),
+    re-stamps snippet reference locations as canonical, and recomputes the
+    accounting. Reach for it when the ledger must be current before you act —
+    a classification batch about to run, a coverage question asked directly —
+    rather than waiting on the background seed an enter_project triggers.
+
+    Takes seconds, not milliseconds (it moves repo archives). Requires write
+    access to the project. Errors name the fix: no forge connection → the
+    owner adds one (Settings → Integrations → Git Forges); no served repo →
+    bind_repo on a host a connection serves.
+
+    Returns the accounting payload — total, accounted, counts by status,
+    unclassified, repos, largest_gaps — plus `pattern_coverage`, the same
+    one-line summary enter_project carries.
+    """
+    uid = current_user_id()
+    coverage = await coverage_svc.refresh_for_caller(uid, project_id)
+    return {
+        "pattern_coverage": coverage_svc.coverage_line(coverage),
+        **coverage,
+    }
+
+
 def register(mcp) -> None:
-    for fn in (classify_shapes, list_shapes):
+    for fn in (classify_shapes, list_shapes, refresh_pattern_coverage):
         mcp.tool(name=fn.__name__)(fn)