docs(standards): split genericity matrix and infra adapters into Tier A/B/C

standards/src/lib/09_infra_adaptors.md

@@ -3,7 +3,9 @@
 ## Summary
 
 All external systems are reached through adapters in `infra/`. Prefer an
-existing internal library over writing a new adapter.
+existing internal library over writing a new adapter; where no library exists,
+copy the Tier B scaffold from `templates/app`. See the Genericity Matrix for the
+Tier A / B / C split.
 
 ---
 
@@ -31,11 +33,13 @@ existing internal library over writing a new adapter.
 
 - Transactions use a session context manager provided by the library.
 
-**Library:** the Mongo operations library (see registry). Do not write raw
-Motor calls in the domain.
+**Tier A — Library (Mongo Ops).** Do not write raw Motor calls in the domain;
+consult the registry and the library's MCP before touching the driver.
 
 ## HTTP response cache
 
+**Tier B — template.** Copy from `templates/app`; not a standalone library.
+
 A generic GET cache sits behind a decorator.
 
 ```python
@@ -50,6 +54,8 @@ async def list_items(request): ...
 
 ## Event / progress bus
 
+**Tier B — template.** Copy from `templates/app`.
+
 A port with an in-memory default adapter (`publish`, `get_events`). Swap for a
 durable broker in production (see Worker & Progress).
 
@@ -59,10 +65,12 @@ External fetchers (files, mail, HTTP) are adapters that wrap ingestion
 libraries. Construct them in the composition root and inject into
 orchestrators.
 
-**Libraries:** the ingestion library (formats) and the mail library (email).
+**Tier A — Libraries:** Omniread (formats) and Mail Intake (email).
 
 ## LLM clients
 
+**Tier B — template.** Copy the pool scaffold from `templates/app`.
+
 When a pipeline calls a model provider, route through a pool adaptor that
 handles provider selection, retries, and client lifecycle:
 
@@ -75,10 +83,17 @@ Providers are selected by `LLM_PROVIDER` and configured by environment.
 
 ## Key-value store
 
+**Tier B — template.** Copy from `templates/app`.
+
 For report/snapshot storage, provide a pluggable store port with a Redis
 adapter and an in-memory fallback.
 
 ## Rule
 
-If a capability already exists as a library (DB, DI, ingestion, mail, auth,
-docs), **use it**. Writing a private copy of a library is a defect.
+- **Tier A (libraries: DB, DI, ingestion, mail, auth, docs, pipelines)** — use
+  the library; writing a private copy is a defect. Query `find_library` first.
+- **Tier B (cache, progress bus, LLM pool, KV store, composition shape, worker,
+  tests)** — these are template code, not libraries: copy them from
+  `templates/app` rather than searching the registry.
+- **Tier C (models, business logic, pipeline families, rules)** — author them
+  yourself.