fix(6470): a moment proposal counts only opens no hook explained, and asks the reader to judge it

The signal counted every get_rule open against every moment from the
previous three minutes, so a rule a search arm had just shown was
proposed for whatever moment happened to fire. All nine pending signal
proposals were wrong.

- The hook skips an open of a rule a hook named this session, and sends
  the last three acts from 90 seconds instead of 30 from 180.
- A rule already mounted anywhere gathers no signal evidence.
- A signal pair keeps the actions that reached its moment and shows them
  as its why.
- The proposal line says it is co-occurrence, not a recommendation, and
  asks the reader to check the rule against the moment before offering
  it; moments.md says the same.

Plugin 2026.10.26.2029.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugin/hooks/grimoire_record_opened.sh

@@ -72,19 +72,29 @@ printf '%s\n' "$rule_id" | grimoire_rules_append "$state_dir/${safe_sid}.opened.
 
 # ── What came just before the open ───────────────────────────────────────
 #
-# grimoire_moment.sh writes every call to `grimoire-moment/<sid>.acts`. The ones
-# from the last three minutes go to the server with this rule's id: a rule
-# opened just after a moment fired is evidence it belongs on that moment, and
-# once that repeats across sessions the server answers with one line asking
-# the reader to offer the operator the mount. Nothing is mounted by this.
+# grimoire_moment.sh writes every call to `grimoire-moment/<sid>.acts`. The
+# last three, from the last ninety seconds, go to the server with this rule's
+# id: a rule the agent went and opened right after a moment fired is evidence
+# it belongs on that moment, and once that repeats across sessions the server
+# answers with one line putting the question to the reader. Nothing is
+# mounted by this.
+#
+# An open of a rule a hook has just NAMED is not reported. A ranked arm or a
+# moment line put it in front of the reader, and that explains the open; the
+# moment beside it did not, so counting it would propose mounts on whatever
+# moment happened to fire while search was surfacing the rule. The window is
+# short for the same reason: a few minutes of agent work reaches many moments.
 command -v curl >/dev/null 2>&1 || exit 0
 grimoire_config || exit 0
+case ",$(grimoire_rules_live "$state_dir/${safe_sid}.rules.ids")," in
+  *",${rule_id},"*) exit 0 ;;
+esac
 acts_file="${TMPDIR:-/tmp}/grimoire-moment/${safe_sid}.acts"
 [ -f "$acts_file" ] || exit 0
 now=$(date +%s 2>/dev/null) || exit 0
-acts=$(awk -F '\t' -v since=$((now - 180)) \
+acts=$(awk -F '\t' -v since=$((now - 90)) \
   '$1 + 0 >= since { sub(/^[^\t]*\t/, ""); print }' "$acts_file" 2>/dev/null \
-  | tail -n 30 | paste -sd ',' - 2>/dev/null)
+  | tail -n 3 | paste -sd ',' - 2>/dev/null)
 [ -n "$acts" ] || exit 0
 
 sid_esc=$(printf '%s' "$session_id" | grimoire_json_escape) || exit 0