feat(ledger): write-path stamping — a pulled canon the session then instantiates lands as a hook instance row (#2791, milestone 294 step 5)

The prior-art hook now names the shapes being written (shapes=kind:name —
every definition in the payload, or the one enclosing an Edit found by
walking the file upward) and the server stamps them as instance rows when
the session PULLED a snippet inside PULL_WINDOW that the payload references
by symbol or that the semantic arm scored for this very payload.
classified_by=hook, evidence in reason; never overrides a judgment or a
canonical row, overridable by classify_shapes. Offered-but-unopened stamps
nothing. Pulled-and-already-seen snippets stay in the semantic query as
evidence without re-entering the deduped menu. A brand-new shape gets a
provisional row the next sync confirms or vanishes. Read-scoped keys get
the hint, never the stamp. Plugin 0.1.34.

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

src/scribe/routes/plugin.py

@@ -127,6 +127,15 @@ async def write_path_prior_art():
                              surfaced. A separate channel on purpose: a reuse
                              hint shown early must not suppress the record-sync
                              nudge when the recorded file is edited later.
+        shapes (opt)       — comma-separated `kind:name` definitions the hook
+                             found in (or enclosing) the payload, kind being
+                             css|sym. The shape ledger's write-path feed
+                             (#2791): when the session recently PULLED a
+                             snippet this payload references or resembles,
+                             these land as instance rows (classified_by=hook).
+                             Honoured only for a caller allowed to write — a
+                             read-scoped key still gets the hint, and never
+                             changes accounting on a GET.
     """
     path = (request.args.get("path") or "").strip()
     code = request.args.get("code") or ""
@@ -149,14 +158,40 @@ async def write_path_prior_art():
         int(p) for p in (request.args.get("exclude_sync_ids") or "").split(",")
         if p.strip().isdigit()
     ]
+    shapes = _parse_shapes(request.args.get("shapes") or "")
+    api_key = getattr(g, "api_key", None)
+    may_stamp = api_key is None or getattr(api_key, "scope", "") == "write"
 
     result = await plugin_ctx_svc.build_write_path_hint(
         g.user.id, path, code=code, project_id=project_id,
         exclude_ids=exclude_ids, exclude_sync_ids=exclude_sync_ids,
+        stamp_shapes=shapes if may_stamp else None,
+        repo_key=repo_bindings_svc.normalize_repo_key(repo) if repo else "",
     )
     return jsonify(result)
 
 
+# The hook names at most a dozen definitions per write; anything past that is
+# a generated file, not a shape being instantiated.
+_SHAPES_CAP = 12
+
+
+def _parse_shapes(raw: str) -> list[tuple[str, str]]:
+    """`css:btn-primary,sym:onTrash` → [("css", "btn-primary"), ("sym", "onTrash")].
+    Unknown kinds and empty names are dropped, duplicates collapse, and the
+    list is capped — the hook's own cap, re-applied so the contract holds
+    for any caller."""
+    out: list[tuple[str, str]] = []
+    for part in raw.split(","):
+        kind, _sep, name = part.strip().partition(":")
+        kind, name = kind.strip(), name.strip()
+        if kind in ("css", "sym") and name and (kind, name) not in out:
+            out.append((kind, name))
+        if len(out) >= _SHAPES_CAP:
+            break
+    return out
+
+
 @plugin_bp.get("/processes")
 @login_required
 async def process_manifest():