fix(ledger): proposer v3 — sym bases gated by language family, reference skips generic verbs, semantic held to the shape's own project (#2871, milestone 294)

The 2026-08 audit examined 407 proposals. Every cross-language hit was wrong:
the Python MCP tool-module canon (symbol `register`) was offered for each auth
view's handleSubmit (it calls authStore.register()) and for the TS auth store's
own `register`; Minstrel/Forge TS canon matched Python bodies by resemblance.
Every cross-project semantic proposal was noise.

- Canon carries the snippet's language; match_canon skips a sym canon whose
  family (py / js / css / sh / sql, by language ↔ by path extension) differs
  from the shape's. Unknown on either side = no gate.
- The reference basis ignores a stoplist of generic verbs (register, load,
  save, get, …): a bare mention is not a call site of THIS canon; the symbol
  basis still catches a second definition, and the call-site relation moves
  to `uses` edges with #2870.
- The semantic arm only reaches canon in the shape's own project and family;
  symbol/text still reach family canon elsewhere (note 2786).
- _PROPOSER_VERSION 2 → 3 so standing proposals re-examine on the next refresh.

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

src/scribe/services/shape_ledger.py

@@ -718,7 +718,9 @@ _SEMANTIC_CAP = 150
 _SEMANTIC_FLOOR = 0.8
 # Bump when a basis's rule changes: rows remember the (body, ruleset) they
 # were examined under, so a tightened rule re-examines everything once.
-_PROPOSER_VERSION = 2
+# v3: language-family gate on the sym bases, reference stoplist, semantic
+# restricted to the shape's own project (#2871).
+_PROPOSER_VERSION = 3
 # Signature resemblance floor, name blanked (difflib ratio) — and a length
 # floor, because `def NAME():` resembles `def NAME(x):` at 0.95 while saying
 # nothing; a family shape has parameters to resemble.
@@ -737,6 +739,64 @@ class Canon(NamedTuple):
     signature: str
     code_norm: str
     project_id: int = 0
+    language: str = ""   # the snippet's recorded language; "" = unknown, no gate
+
+
+# Language families: the sym bases only propose within one. The 2026-08
+# audit (#2871) found every cross-language hit wrong — a Python tool-module
+# canon named `register` proposed for Vue `handleSubmit`s that call
+# `authStore.register()`, and a TS store's `register` matched it by symbol;
+# Minstrel/Forge TS canon proposed for Python bodies by resemblance. CSS is
+# its own kind and is not gated here.
+_FAMILY_BY_LANG = {
+    "python": "py", "py": "py",
+    "typescript": "js", "ts": "js", "tsx": "js", "javascript": "js", "js": "js",
+    "jsx": "js", "vue": "js", "mjs": "js", "cjs": "js",
+    "css": "css", "scss": "css", "sass": "css", "less": "css",
+    "bash": "sh", "sh": "sh", "shell": "sh", "zsh": "sh",
+    "sql": "sql",
+}
+_FAMILY_BY_EXT = {
+    ".py": "py", ".pyi": "py",
+    ".ts": "js", ".tsx": "js", ".js": "js", ".jsx": "js", ".vue": "js", ".mjs": "js", ".cjs": "js",
+    ".css": "css", ".scss": "css", ".sass": "css", ".less": "css",
+    ".sh": "sh", ".bash": "sh", ".zsh": "sh",
+    ".sql": "sql",
+}
+
+
+def language_family(language: str) -> str:
+    """The family a recorded snippet language belongs to ("" when unknown)."""
+    return _FAMILY_BY_LANG.get((language or "").strip().lower(), "")
+
+
+def path_family(path: str) -> str:
+    """The family a file path belongs to, by extension ("" when unknown)."""
+    p = (path or "").lower()
+    for ext, fam in _FAMILY_BY_EXT.items():
+        if p.endswith(ext):
+            return fam
+    return ""
+
+
+def same_family(path: str, canon_language: str) -> bool:
+    """A sym basis may propose this canon for this path: both families known
+    and equal, or either unknown (no evidence either way → no gate)."""
+    a = path_family(path)
+    b = language_family(canon_language)
+    return not a or not b or a == b
+
+
+# Reference basis: generic verbs name too many unrelated things to count a
+# bare mention as a call site of THIS canon (`register`, `load`, `save` …).
+# The symbol basis still catches a second definition of such a name; the
+# call-site relation for these becomes a `uses` edge once #2870 lands.
+_REFERENCE_STOPLIST = frozenset({
+    "get", "set", "put", "post", "load", "save", "run", "main", "init", "setup",
+    "register", "restore", "reset", "toggle", "close", "open", "submit", "handler",
+    "update", "create", "delete", "remove", "add", "start", "stop", "send",
+    "receive", "render", "mount", "dispatch", "call", "apply", "execute",
+})
 
 
 def _norm_text(text: str) -> str:
@@ -789,11 +849,17 @@ def match_canon(
     for c in canons:
         if c.kind != kind:
             continue
+        if kind == "sym" and not same_family(path, c.language):
+            continue  # a Python canon says nothing about a Vue body, and vice versa
         if c.symbol and _norm_symbol(c.symbol) == norm_sym:
             if not any(location_covers(lp, ls, path, symbol) for lp, ls in c.locations):
                 offer("symbol", 1.0, c)
             continue  # its own location is canonical territory, not a proposal
-        if c.symbol and references_symbol(body, c.symbol, kind):
+        if (
+            c.symbol
+            and _norm_symbol(c.symbol).lower() not in _REFERENCE_STOPLIST
+            and references_symbol(body, c.symbol, kind)
+        ):
             offer("reference", 0.9, c)
         if c.code_norm and text_contains(body, c.code_norm):
             offer("text", 0.95, c)
@@ -849,6 +915,7 @@ async def canon_catalog(user_id: int) -> list[Canon]:
                 for loc in fields.get("locations") or []
             ),
             signature, _norm_text(code), int(note.project_id or 0),
+            (fields.get("language") or "").strip().lower(),
         ))
     return out
 
@@ -907,7 +974,14 @@ async def propose_for_repo(
     if canons is None:
         canons = await canon_catalog(user_id)
     by_key = {(d[0], d[1], d[2]): d for d in definitions}
-    sym_canon_ids = {c.snippet_id for c in canons if c.kind == "sym"}
+    # The semantic arm is the widest net and, across projects, was pure noise
+    # in the 2026-08 audit (#2871): it is held to the shape's own project and
+    # language family. The precise bases (symbol/text) still reach family
+    # canon in other projects (note 2786).
+    sym_canons = [c for c in canons if c.kind == "sym" and c.project_id == project_id]
+
+    def semantic_allowed(path: str) -> set[int]:
+        return {c.snippet_id for c in sym_canons if same_family(path, c.language)}
     now = datetime.now(timezone.utc)
     examined = proposed = checked = 0
     async with async_session() as session:
@@ -955,7 +1029,7 @@ async def propose_for_repo(
                 continue
             checked += 1
             try:
-                found = await _semantic_canon(user_id, d[5], sym_canon_ids)
+                found = await _semantic_canon(user_id, d[5], semantic_allowed(row.path))
             except Exception:
                 logger.warning("semantic proposal failed", exc_info=True)
                 found = None