feat(moments): mount the corpus by proposal - a pass and an open-after-moment signal, both stopping at the operator (milestone 458 step 7, #4925)

A rule written before moments existed is mounted on nothing. Step 7 records,
per (rule, moment), whether it belongs there and who said so:

- rule_moment_judgments (migration 0118, backup v23): suggested / confirmed /
  rejected, from a pass, the signal, or an edit. Moment "" is "no moment fits".
- The pass: rules_to_mount lists unjudged rules; propose_rule_moments records
  suggestions that mount nothing; rule_moment_proposals and
  judge_rule_moments put them to the operator. A confirm mounts, a reject is
  kept so the pair is never proposed again. Same service behind REST and a
  "Waiting on you" panel in Settings > Moments.
- Edits are judgments: set_rule_moments, the one mount write path, confirms
  what was added and rejects what was removed in the same transaction.
- The signal: scribe_moment.sh keeps a per-session acts ledger; when a rule
  is opened, scribe_record_opened.sh sends the last three minutes of it to
  /api/plugin/rule-opened. The acts resolve through the install's mappings;
  work.run and work.change are not evidence. Counted per distinct session
  with lesson_rules' evidence model, and once due the open returns one line
  asking the reader to offer the mount.
- scribe_session_end.sh removes the session's scribe-moment files.

Plugin 2026.10.05.2003.

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

plugin/hooks/scribe_session_end.sh

@@ -24,18 +24,24 @@ set -uo pipefail
 # shellcheck source=plugin/hooks/scribe_defs.sh
 . "$(dirname "${BASH_SOURCE[0]}")/scribe_defs.sh"
 
-command -v curl >/dev/null 2>&1 || exit 0
-scribe_config || exit 0
-
 event=$(cat 2>/dev/null || true)
 [ -n "$event" ] || exit 0
 
 event_flat=$(printf '%s' "$event" | scribe_json_flat)
+session_id=$(scribe_json_pick "$event_flat" '.session_id')
+[ -n "$session_id" ] || exit 0
+
+# The moment arm's per-session files (its tool cache and the acts ledger,
+# milestone 458) describe a session that is over, on any exit — a clear
+# included, since the next conversation is a new session id.
+safe_sid=$(printf '%s' "$session_id" | tr -c 'A-Za-z0-9._-' '_')
+rm -f "${TMPDIR:-/tmp}/scribe-moment/${safe_sid}".* 2>/dev/null || true
+
 reason=$(scribe_json_pick "$event_flat" '.reason')
 [ "$reason" = "clear" ] && exit 0
 
-session_id=$(scribe_json_pick "$event_flat" '.session_id')
-[ -n "$session_id" ] || exit 0
+command -v curl >/dev/null 2>&1 || exit 0
+scribe_config || exit 0
 
 sid_enc=$(printf '%s' "$session_id" | scribe_urlenc) || exit 0
 curl -fsS --max-time 4 \