feat(reuse): recording model becomes the pattern library — every shape at first build (#2687)

Decision #2686: snippets are the project's pattern library, not a dedup
net. The floor, the reusing-code skill, and the snippet tool docstrings
now state the proactive model — record every shape the first time it is
built, with no will-it-recur judgment, and start later instances from
the recorded shape; second-copy consolidation stays as the backstop.
The floor guard test pins all three elements (tool, first-build trigger,
backstop) so the model cannot silently regress to the reactive wording.

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

src/scribe/mcp/tools/snippets.py

@@ -23,7 +23,12 @@ async def list_snippets(
     q: str = "", tag: str = "", limit: int = 50, project_id: int = 0,
     repo: str = "", path: str = "", symbol: str = "", verification: str = "",
 ) -> dict:
-    """List recorded snippets (reusable functions/components).
+    """List recorded snippets — the project's pattern library.
+
+    Search here BEFORE building any shape (a component, control, route
+    handler, service class, helper, scaffold): a recorded shape is the
+    starting point for every later instance, and building without checking is
+    how the same button ends up defined four diverging ways.
 
     Two ways to ask, usable together: by MEANING (`q` — "what do I need this code
     to do?") and by PLACE (`repo`/`path`/`symbol` — "what canonical helpers
@@ -101,13 +106,18 @@ async def create_snippet(
     system_ids: list[int] | None = None,
     force: bool = False,
 ) -> dict:
-    """Record a reusable function/component so future sessions can RECALL it
-    instead of writing a fresh one-off.
+    """Record a shape in the project's pattern library, so every later
+    instance starts from it instead of re-deriving it.
 
-    Reach for this the moment you build (or notice) something reusable: a helper,
-    a hook, a component, a pattern worth repeating. Recording it once makes it
-    surface automatically when a similar problem comes up later. Before writing a
-    new utility, search first — a snippet may already exist.
+    Reach for this the FIRST time any shape is built — a component, a control,
+    a route handler, a service class, a helper, a test scaffold — not only
+    when something is judged "reusable": the builder of the first instance
+    can't know what will recur, and a missed record is invisible until it
+    resurfaces as an uninformed duplicate. Over-recording is safe (dead weight
+    shows in the usage counters and can be pruned); under-recording has no
+    signal. A deliberate departure from a recorded shape is recorded as its
+    own named variant, not left as drift. Before building, search first — the
+    shape may already be recorded.
 
     Args:
         name: Short name of the function/component, e.g. "useDebouncedRef".