Update federation implementation notes

docs/federation-implementation-notes.md

@@ -174,7 +174,7 @@ amduat_asl_store_error_t amduat_fed_resolve(
 Notes:
 - Transport fetch is not part of resolve; it only consumes ingested records.
 - The daemon can choose to fetch missing bytes when resolve reports a remote
-  location but local bytes are absent.
+  reference but local bytes are absent.
 - If per-record filtering is enabled, it is applied during ingest or view build
   and any denials are recorded in view metadata (e.g., a table of
   amduat_fed_policy_deny_t).
@@ -200,6 +200,14 @@ Federation view storage MAY be:
 If remote bytes are fetched, they MUST be written to a cache store that is
 logically separate from the authoritative local store (policy-controlled).
 
+## Federation API overview
+
+Core federation primitives are exposed via:
+- include/amduat/fed/registry.h
+- include/amduat/fed/ingest.h
+- include/amduat/fed/replay.h
+- include/amduat/fed/view.h
+
 ## Policy gating
 
 - Admission gating is per-domain.
@@ -220,6 +228,12 @@ Notes:
   the denial in view metadata. Resolve MAY return POLICY_DENIED only when such a
   denial is recorded for the queried key; otherwise it MUST return NOT_FOUND.
 
+## Remote fetch guidance
+
+Core resolve returns only artifact references. The middle layer is responsible
+for fetching remote bytes by reference over its transport and caching them
+separately from the authoritative local store.
+
 ## Tests (minimal)
 
 1) Replay ordering determinism across two domains with interleaved logseq.