fix(ledger): the proposer prefers a same-project canon on a tie — family canon elsewhere is the fallback, not the first hit

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

tests/test_shape_ledger.py

@@ -190,9 +190,24 @@ def test_text_containment_is_whitespace_insensitive_with_a_floor():
     assert not text_contains("x = 1", "x = 1")          # below the substance floor
 
 
-def _canon(sid, kind="sym", symbol="", locations=(), signature="", code=""):
+def _canon(sid, kind="sym", symbol="", locations=(), signature="", code="", project_id=0):
     from scribe.services.shape_ledger import Canon, _norm_text
-    return Canon(sid, kind, symbol, tuple(locations), signature, _norm_text(code))
+    return Canon(sid, kind, symbol, tuple(locations), signature, _norm_text(code), project_id)
+
+
+def test_match_canon_prefers_the_shapes_own_project_on_a_tie():
+    """The same helper recorded in two projects: the shape's own project's
+    record is its canon; family canon elsewhere is the fallback."""
+    from scribe.services.shape_ledger import match_canon
+    family = _canon(3, "sym", "slugify", [("lib/text.py", "slugify")], project_id=1)
+    own = _canon(4, "sym", "slugify", [("src/util/text.py", "slugify")], project_id=2)
+    assert match_canon("sym", "src/other.py", "slugify", "def slugify(t):", "",
+                       [family, own], project_id=2) == (4, "symbol", 1.0)
+    assert match_canon("sym", "src/other.py", "slugify", "def slugify(t):", "",
+                       [family, own], project_id=1) == (3, "symbol", 1.0)
+    # No project given → first-best stands; nothing breaks.
+    assert match_canon("sym", "src/other.py", "slugify", "def slugify(t):", "",
+                       [family, own])[1] == "symbol"
 
 
 def test_match_canon_orders_bases_strongest_first_and_respects_kind():