feat(reuse): recording gets a seam — the prior-art hook asks for create_snippet when duplication is proven and unrecorded (#2664)

Zero snippets were ever recorded outside sessions already thinking about
snippets: the read side had a real seam (the PreToolUse hook) and the record
side had a trailing clause of a floor bullet. The trigger moment — 'I just
wrote the second copy' — is mid-Write/Edit, so the nudge now rides the same
hook: when the local arm proves the definition exists elsewhere in the repo
AND Scribe returned no record of it, the context block asks for
create_snippet. Both gates or silence, so a brand-new helper and an
already-recorded one stay nudge-free.

Floor bullet promoted to name the trigger moments (extract, hoist, second
copy); guarded by test the same way the Systems reflex is. Plugin 0.1.29 so
the cache picks up the hook (#2209).

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

tests/test_instruction_surfaces_agree.py

@@ -128,6 +128,25 @@ def test_floor_states_the_systems_reflex():
         )
 
 
+def test_floor_names_the_snippet_recording_triggers():
+    """The recording half of reuse needs NAMED trigger moments on the floor.
+
+    #2664's behavioral finding: with recording guidance as a trailing clause of
+    the reuse bullet, zero snippets were ever recorded outside sessions already
+    thinking about snippets — extracting a shared component (Roundtable's
+    BaseModal) produced task prose and no record. The floor must name the
+    moments, not just the tool.
+    """
+    floor = (ROOT / "plugin" / "hooks" / "scribe_static_context.md").read_text()
+    for needle in ("create_snippet", "second copy"):
+        assert needle in floor, (
+            f"plugin/hooks/scribe_static_context.md no longer states the "
+            f"snippet-recording trigger ({needle!r}) — the record-as-you-build "
+            f"reflex must be stated on the floor with its trigger moments "
+            f"(#2664)."
+        )
+
+
 # Topics displaced from _INSTRUCTIONS when it was cut to fit the fold. Each
 # must remain stated on at least one DELIVERED surface: a tool docstring
 # (arrives with the tool schema), the plugin static context (always arrives),