feat(shapes): the write-path hook suggests and no longer stamps (milestone 439 step 4)

The hook used to land its evidence as `instance` rows, classified_by=hook —
a permanent verdict nobody read, and the source of the weak stamps that
poisoned two ledgers (#4608). Now the agent that wrote the code judges it at
the end of the turn, and the hook's evidence is what it is shown.

- shape_ledger.suggest_write_path_instances (was stamp_write_path_instances):
  same evidence and form gate, but it writes a PROPOSAL — proposed_snippet_id,
  basis "reference" (named) or "semantic" (resembles), score — and never a
  status. A judged row is left alone; a new shape gets an unclassified
  provisional row so the suggestion reaches the end-of-turn question as
  "looks like #N". By-name uses edges stay: a fact, not a verdict.
- The prior-art line says "looks like #N … when you judge this turn's
  shapes, say whether it is", and the result key is `suggested`.
- write_time_divergence takes `suggested`; _RESEMBLE_MIN re-documented as the
  suggestion bar and the weak-stamp line.
- reusing-code skill no longer says the pull stamps an instance.
- Tests moved to the new contract, plus a guard that nothing the hook does
  writes classified_by="hook".

Plugin version minted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/services/plugin_context.py

@@ -2083,16 +2083,18 @@ async def build_write_path_hint(
     ``stamp_shapes`` turns the same request into the ledger's write-path feed
     (#2791): the (kind, name) definitions the hook saw in — or enclosing —
     the payload. When the session has PULLED a snippet recently and this
-    payload references or resembles it, those shapes land as `instance` rows
-    (classified_by=hook, see shape_ledger.stamp_write_path_instances) and
-    the result's ``stamped`` lists them. The route passes it only for a
-    caller allowed to write — a read-scoped key gets the hint, never the
-    stamp. ``repo_key`` (the hook's remote, normalised) homes a provisional
-    row for a shape the ledger has not synced yet.
+    payload references or resembles it, those shapes carry it as a PROPOSAL
+    (see shape_ledger.suggest_write_path_instances) and the result's
+    ``suggested`` lists them. Never a verdict since milestone 439: the agent
+    that wrote the code judges it at the end of the turn, shown this as
+    evidence. The route passes it only for a caller allowed to write — a
+    read-scoped key gets the hint, never a ledger write. ``repo_key`` (the
+    hook's remote, normalised) homes a provisional row for a shape the
+    ledger has not synced yet.
     """
     cfg = await get_writepath_config(user_id)
     empty = {"context": "", "note_ids": [], "sync_note_ids": [], "config": cfg,
-             "stamped": [], "divergence": [], "derive": [], "derive_keys": [],
+             "suggested": [], "divergence": [], "derive": [], "derive_keys": [],
              "rule_ids": []}
     path = (path or "").strip()
     if not cfg["enabled"] or not path:
@@ -2356,18 +2358,18 @@ async def build_write_path_hint(
 
     menu = (placed + scored)[:max(0, top_k - len(synced))]
 
-    # The stamp runs whether or not anything is rendered — after dedup, the
-    # common case is a silent hint and a pulled canon being instantiated.
-    stamped: list[dict] = []
+    # The suggestion runs whether or not anything is rendered — after dedup,
+    # the common case is a silent hint and a pulled canon being instantiated.
+    suggested: list[dict] = []
     if stamp_shapes and pulled:
         try:
-            stamped = await shape_ledger_svc.stamp_write_path_instances(
+            suggested = await shape_ledger_svc.suggest_write_path_instances(
                 user_id, project_id, path=path, shapes=stamp_shapes,
                 code=code or "", pulled=pulled, resembles=resembles,
                 repo_key=repo_key,
             )
         except Exception:
-            logger.warning("Write-path ledger stamping failed", exc_info=True)
+            logger.warning("Write-path ledger suggestion failed", exc_info=True)
     # The in-band button-B check (#2793): the hook named the shapes being
     # written; if this directory+kind is canon-dense and a named shape isn't
     # (about to be) an instance of that canon, say so NOW — at the write,
@@ -2376,7 +2378,7 @@ async def build_write_path_hint(
     if stamp_shapes and project_id:
         try:
             divergence = await shape_ledger_svc.write_time_divergence(
-                project_id, path, stamp_shapes, stamped, code or "",
+                project_id, path, stamp_shapes, suggested, code or "",
             )
         except Exception:
             logger.warning("write-time divergence check failed", exc_info=True)
@@ -2430,7 +2432,7 @@ async def build_write_path_hint(
     design_text, design_dedup = await _design_arm(
         user_id, project_id, path, set(exclude_derive or []),
     )
-    if not staleness and not synced and not menu and not stamped and not divergence and not derive:
+    if not staleness and not synced and not menu and not suggested and not divergence and not derive:
         if design_text:
             return {**empty, "context": design_text, "derive_keys": [design_dedup]}
         return empty
@@ -2531,8 +2533,8 @@ async def build_write_path_hint(
         if passage:
             lines.append(f">   ↳ {passage}")
 
-    if stamped:
-        lines.append(_stamp_line(path, stamped))
+    if suggested:
+        lines.append(_suggest_line(path, suggested))
     if divergence:
         lines.append(_divergence_line(path, divergence))
     if derive:
@@ -2694,7 +2696,7 @@ async def build_write_path_hint(
         "note_ids": note_ids,
         "sync_note_ids": sync_note_ids,
         "config": cfg,
-        "stamped": stamped,
+        "suggested": suggested,
         "divergence": divergence,
         "derive": derive,
         "derive_keys": [d["key"] for d in derive] + (
@@ -3017,22 +3019,23 @@ def _divergence_line(path: str, divergence: list[dict]) -> str:
     )
 
 
-def _stamp_line(path: str, stamped: list[dict]) -> str:
-    """One line saying what the ledger just recorded, so the session can
-    correct a wrong stamp in the moment rather than an audit finding it."""
+def _suggest_line(path: str, suggested: list[dict]) -> str:
+    """One line naming the recorded shape this code looks like, as evidence
+    for the judgment the agent gives at the end of the turn (milestone 439)
+    — not a record of one already made."""
     by_snippet: dict[int, list[str]] = {}
-    for row in stamped:
+    for row in suggested:
         label = f".{row['symbol']}" if row["kind"] == "css" else row["symbol"]
         by_snippet.setdefault(int(row["snippet_id"]), []).append(f"`{label}`")
     parts = [
-        f"{', '.join(names)} → instance of #{sid}"
+        f"{', '.join(names)} → looks like #{sid}"
         for sid, names in by_snippet.items()
     ]
     return (
-        f"> Shape accounting: recorded at `{path}` — {'; '.join(parts)} "
-        "(classified_by=hook: you pulled that snippet this session and this "
-        "code references/resembles it). Not an instance? `classify_shapes` "
-        "overrides a hook stamp."
+        f"> Shape accounting: at `{path}` — {'; '.join(parts)} "
+        "(you pulled that snippet this session and this code names or resembles "
+        "it). When you judge this turn's shapes, say whether it is: `instance` "
+        "of it, `variant` with the why, or something else."
     )