docs: add 30-day expiry callout + ship 4 auto-save tools

Adds a brief [!IMPORTANT] callout at the top of the README pointing
users to the urgent announcement at #1388. Claude Code auto-deletes
local JSONL transcripts after 30 days; users without the auto-save
hooks wired are losing transcript data off the rolling window.

Ships 4 small standalone tools at tools/:
- backup_claude_jsonls.sh — rsync ~/.claude/projects/ to a safe folder
- render_jsonl.py — convert JSONL transcripts to readable text
- find_orphan_claude_jsonls.sh — scan backup locations for orphan
  Claude Code transcripts (multi-line shape detection + topic preview)
- save.md — Claude Code slash command for manual /save into MemPalace

Tools verified by independent agent against v3.3.4 source.
Read-only on user data. POSIX bash + Python stdlib only.

tools/backup_claude_jsonls.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# backup_claude_jsonls.sh
+#
+# Claude Code stores every conversation as a JSONL transcript at
+#   ~/.claude/projects/<encoded-project>/<session-uuid>.jsonl
+# Anthropic auto-deletes those files after 30 DAYS:
+#   https://docs.claude.com/en/docs/claude-code/data-usage
+#
+# This script copies them, read-only, into ~/Documents/Claude_JSONL_Backup/
+# so the 30-day clock no longer applies. Re-run any time — rsync is incremental.
+# It NEVER deletes, modifies, or touches files inside ~/.claude/.
+
+set -eu
+
+SRC="${HOME}/.claude/projects/"
+DST="${HOME}/Documents/Claude_JSONL_Backup/"
+
+[ -d "$SRC" ] || { echo "ERROR: $SRC does not exist."; exit 1; }
+mkdir -p "$DST"
+
+echo "Backing up $SRC -> $DST"
+rsync -a --times "$SRC" "$DST"
+
+src_count=$(find "$SRC" -type f -name '*.jsonl' | wc -l | tr -d ' ')
+dst_count=$(find "$DST" -type f -name '*.jsonl' | wc -l | tr -d ' ')
+oldest=$(find "$DST" -type f -name '*.jsonl' -exec stat -f '%Sm %N' -t '%Y-%m-%d' {} \; 2>/dev/null \
+        || find "$DST" -type f -name '*.jsonl' -printf '%TY-%Tm-%Td %p\n' 2>/dev/null)
+oldest_date=$(echo "$oldest" | sort | head -n 1 | awk '{print $1}')
+newest_date=$(echo "$oldest" | sort | tail -n 1 | awk '{print $1}')
+
+echo "Source JSONL count : $src_count"
+echo "Backup JSONL count : $dst_count"
+echo "Oldest backup file : ${oldest_date:-n/a}"
+echo "Newest backup file : ${newest_date:-n/a}"
+
+if [ "$src_count" -ne "$dst_count" ]; then
+  echo "FAIL: count mismatch ($src_count vs $dst_count)"; exit 2
+fi
+echo "OK: backup verified."