DHARMA network: per-soul Engram instances (8801–8819)

Each soul now gets their own isolated Engram process with a dedicated data
directory (imprints/<slug>/), port, and API key — the DHARMA network.
Neuron's Engram at 8742 is never touched.

- registry.json: add engram_db_path, engram_port, engram_url to all 19 entries
  (Bobby Anderson 8801 → Helen Keller 8819)
- launch_dharma.sh: start all 19 soul Engrams in background; supports
  single-slug filter and skip-if-running detection
- stop_dharma.sh: graceful shutdown via PID file, falls back to port scan
- reinstall_imprints.py: bulk reinstall — starts each Engram temporarily,
  installs seed, records new root_id, stops; supports --slug and --dry-run
- src/install.el: resolves soul's engram_url from registry (never 8742);
  guards against accidental writes to Neuron's shared Engram
- src/summon.el: reads engram_url per-soul from registry; passes it to soul
  server in POST body so soul connects to the right Engram; supports
  both single-soul (engram_url) and multi-soul (engram_urls array) payloads

stop_dharma.sh

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+# DHARMA network — stop all running soul Engrams.
+# Reads PIDs from /tmp/dharma-pids written by launch_dharma.sh.
+# Falls back to killing by port if PID file is missing.
+#
+# Usage:
+#   ./stop_dharma.sh            stop all soul Engrams
+#   ./stop_dharma.sh <slug>     stop a single soul by slug
+
+set -euo pipefail
+
+PID_FILE=/tmp/dharma-pids
+FILTER="${1:-}"
+
+stopped=0
+missed=0
+
+# Kill via PID file if it exists
+if [ -f "$PID_FILE" ]; then
+    while IFS=' ' read -r pid slug port; do
+        [ -z "$pid" ] && continue
+
+        if [ -n "$FILTER" ] && [ "$slug" != "$FILTER" ]; then
+            continue
+        fi
+
+        if kill -0 "$pid" 2>/dev/null; then
+            kill "$pid"
+            echo "[dharma] stopped $slug (pid=$pid port=$port)"
+            stopped=$((stopped + 1))
+        else
+            echo "[dharma] $slug (pid=$pid) already gone"
+        fi
+    done < "$PID_FILE"
+
+    if [ -z "$FILTER" ]; then
+        rm -f "$PID_FILE"
+    fi
+else
+    echo "[dharma] no PID file at $PID_FILE — killing by port scan"
+    # Fall back: kill anything on ports 8801–8819
+    for port in $(seq 8801 8819); do
+        pids=$(lsof -ti tcp:"$port" 2>/dev/null || true)
+        if [ -n "$pids" ]; then
+            echo "[dharma] killing port $port (pids: $pids)"
+            echo "$pids" | xargs kill 2>/dev/null || true
+            stopped=$((stopped + 1))
+        fi
+    done
+fi
+
+echo ""
+echo "[dharma] stopped=$stopped  missed=$missed"