feat(prior-art): edit-time record-sync nudge — the sync class (#2708)

A snippet recorded AT the exact file being edited is not a reuse
suggestion — it IS the record of the file being changed. The write-path
hint now renders those as their own SYNC class: 'snippet #N records this
file — updating the record is part of the edit (update_snippet /
verify_snippet)'. Nearby and semantic hits stay the reuse menu.

The two classes dedup on separate per-session channels (exclude_ids vs
exclude_sync_ids, .ids vs .sync.ids in the hook), so a reuse hint shown
early in a session can no longer silence the record-sync nudge when the
recorded file itself is edited later. Sync surfacing is measured under
its own note_usage source (write_path_sync) — its pull-through rate is
the scoreboard for whether edit-time sync actually happens, per decision
#2707 (no forge connection; records stay current in the session that has
the context). Plugin 0.1.31.

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

plugin/hooks/scribe_prior_art.sh

@@ -8,6 +8,12 @@
 # that path or in its directory, plus snippets resembling the code about to be
 # written. Titles + ids only, never bodies.
 #
+# The answer comes in two framings (#2708). A snippet recorded AT the exact
+# file being edited is the SYNC class — "you are editing the recorded file;
+# updating the record is part of the edit" — which is how records stay current
+# on an instance with no forge connection (decision #2707). Everything else is
+# the REUSE menu. The two dedup separately (see the state files below).
+#
 # NEVER BLOCKS. It returns `additionalContext` with no `permissionDecision`, so
 # the write proceeds untouched and Claude sees the note beside the tool result.
 # Any failure — unconfigured, unreachable, malformed — exits 0 in silence. A
@@ -194,31 +200,51 @@ fi
 # surface shows a given snippet at most once per session, but they don't silence
 # each other: a title that flew past in a prompt menu twenty turns ago is
 # exactly what should reappear at the moment the duplicate is being written.
+#
+# TWO channels, not one (#2708). The server answers in two classes — REUSE
+# ("something similar/nearby is recorded") and SYNC ("a snippet records the
+# exact file being edited — updating the record is part of the edit"). They
+# dedup separately: a reuse hint shown early in the session must not suppress
+# the sync nudge when the recorded file itself is edited later.
 state_dir="${TMPDIR:-/tmp}/scribe-priorart"
 mkdir -p "$state_dir" 2>/dev/null || true
 idfile=""
+syncfile=""
 exclude_q=""
+sync_exclude_q=""
 if [ -n "$session_id" ]; then
   safe_sid=$(printf '%s' "$session_id" | tr -c 'A-Za-z0-9._-' '_')
   idfile="$state_dir/${safe_sid}.ids"
+  syncfile="$state_dir/${safe_sid}.sync.ids"
   if [ -f "$idfile" ]; then
     seen=$(tr '\n' ',' < "$idfile" 2>/dev/null | sed 's/,$//')
     [ -n "$seen" ] && exclude_q="&exclude_ids=${seen}"
   fi
+  if [ -f "$syncfile" ]; then
+    sync_seen=$(tr '\n' ',' < "$syncfile" 2>/dev/null | sed 's/,$//')
+    [ -n "$sync_seen" ] && sync_exclude_q="&exclude_sync_ids=${sync_seen}"
+  fi
 fi
 
 # `|| true`, not `|| exit 0`: an unreachable instance must not discard a local
 # finding that needed no instance to produce.
 body=$(curl -fsS --max-time 5 \
   -H "Authorization: Bearer ${token}" \
-  "${url%/}/api/plugin/prior-art?path=${path_enc}&code=${code_enc}${repo_q}${exclude_q}" 2>/dev/null) || body=""
+  "${url%/}/api/plugin/prior-art?path=${path_enc}&code=${code_enc}${repo_q}${exclude_q}${sync_exclude_q}" 2>/dev/null) || body=""
 
 context=""
 if [ -n "$body" ]; then
   context=$(printf '%s' "$body" | jq -r '.context // empty' 2>/dev/null) || context=""
-  # Remember what was surfaced so it isn't shown again this session.
-  if [ -n "$idfile" ] && [ -n "$context" ]; then
-    printf '%s' "$body" | jq -r '.note_ids[]? // empty' 2>/dev/null >> "$idfile" || true
+  # Remember what was surfaced so it isn't shown again this session — each
+  # class into its own channel: sync ids (snippets recording the edited file)
+  # to the sync file, everything else to the reuse file.
+  if [ -n "$context" ]; then
+    if [ -n "$idfile" ]; then
+      printf '%s' "$body" | jq -r '((.note_ids // []) - (.sync_note_ids // []))[]?' 2>/dev/null >> "$idfile" || true
+    fi
+    if [ -n "$syncfile" ]; then
+      printf '%s' "$body" | jq -r '(.sync_note_ids // [])[]?' 2>/dev/null >> "$syncfile" || true
+    fi
   fi
 fi