feat(wip): preserve filters between Overview and Detail with thundering-herd fix

URL is now single source of truth for filter state (workorder, lotid,
package, type, status) across WIP Overview and Detail pages. Drill-down
carries all filters + status; back button dynamically reflects Detail
changes. Backend Detail API now supports pj_type filter parameter.

Harden concurrency: add pagehide abort for MPA navigation, double-check
locking on Redis JSON parse and snapshot build to prevent thread pool
saturation during rapid page switching. Fix watchdog setsid and PID
discovery. Fix test_realtime_equipment_cache RUNCARDLOTID field mismatch.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/start_server.sh

@@ -460,6 +460,16 @@ get_watchdog_pid() {
         fi
         rm -f "$WATCHDOG_PROCESS_PID_FILE"
     fi
+
+    # Fallback: discover watchdog process even if PID file is missing/stale
+    local discovered_pid
+    discovered_pid=$(pgrep -f "[p]ython .*scripts/worker_watchdog.py" 2>/dev/null | head -1 || true)
+    if [ -n "${discovered_pid}" ] && kill -0 "${discovered_pid}" 2>/dev/null; then
+        echo "${discovered_pid}" > "$WATCHDOG_PROCESS_PID_FILE"
+        echo "${discovered_pid}"
+        return 0
+    fi
+
     return 1
 }
 
@@ -481,7 +491,12 @@ start_watchdog() {
     fi
 
     log_info "Starting worker watchdog..."
-    nohup python scripts/worker_watchdog.py >> "$WATCHDOG_LOG" 2>&1 &
+    if command -v setsid >/dev/null 2>&1; then
+        # Start watchdog in its own session so it survives non-interactive shell teardown.
+        setsid python scripts/worker_watchdog.py >> "$WATCHDOG_LOG" 2>&1 < /dev/null &
+    else
+        nohup python scripts/worker_watchdog.py >> "$WATCHDOG_LOG" 2>&1 < /dev/null &
+    fi
     local pid=$!
     echo "$pid" > "$WATCHDOG_PROCESS_PID_FILE"