Add status dashboard, server, scraper stats, and DATA_DIR support

Key changes:
- Replace ratings_server.py + status.html with a unified server.py that
  serves the map, scraper status dashboard, and ratings API in one process
- Add scraper_stats.py utility: each scraper writes per-run stats (fetched,
  accepted, excluded, duration) to stats_<source>.json for the status page
- generate_status.py: respect DATA_DIR env var so status.json lands in the
  configured data directory instead of always the project root
- run_all.sh: replace the {"status":"running"} overwrite of status.json with
  a dedicated scraper_running.json lock file; trap on EXIT ensures cleanup
  even on kill/error, preventing the previous run's results from being wiped
- server.py: detect running state via scraper_running.json existence instead
  of status["status"] field, eliminating the dual-use race condition
- Makefile: add serve (local dev), debug (Docker debug container) targets;
  add SERVER_PORT variable
- build/Dockerfile + entrypoint.sh: switch to server.py, set DATA_DIR,
  adjust volume mounts
- .gitignore: add *.json and *.log to keep runtime data files out of VCS
- mapa_bytu.html: price-per-m² colouring, status link, UX tweaks

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

run_all.sh

@@ -20,8 +20,10 @@ START_TIME=$(date -u +"%Y-%m-%dT%H:%M:%S")
 START_EPOCH=$(date +%s)
 LOG_FILE="$(pwd)/scrape_run.log"
 
-# Mark status as running
-echo '{"status":"running"}' > status.json
+# Mark scraper as running; cleaned up on exit (even on error/kill)
+LOCK_FILE="${DATA_DIR:-.}/scraper_running.json"
+echo '{"running":true,"started_at":"'"$START_TIME"'"}' > "$LOCK_FILE"
+trap 'rm -f "$LOCK_FILE"' EXIT
 
 show_help() {
     echo "Usage: ./run_all.sh [OPTIONS]"
@@ -32,16 +34,19 @@ show_help() {
     echo "  --max-pages N         Maximální počet stránek ke stažení z každého zdroje"
     echo "  --max-properties N    Maximální počet nemovitostí ke stažení z každého zdroje"
     echo "  --log-level LEVEL     Úroveň logování (DEBUG, INFO, WARNING, ERROR)"
+    echo "  --keep N              Počet běhů v historii (výchozí: 5, 0=neomezeno)"
     echo "  -h, --help            Zobrazí tuto nápovědu"
     echo ""
     echo "Examples:"
     echo "  ./run_all.sh                                  # plný běh"
     echo "  ./run_all.sh --max-pages 1 --max-properties 10  # rychlý test"
     echo "  ./run_all.sh --log-level DEBUG                # s debug logováním"
+    echo "  ./run_all.sh --keep 10                        # uchovej 10 běhů v historii"
 }
 
 # Parse arguments
 SCRAPER_ARGS=""
+KEEP_ARG=""
 while [[ $# -gt 0 ]]; do
     case $1 in
         -h|--help)
@@ -52,6 +57,10 @@ while [[ $# -gt 0 ]]; do
             SCRAPER_ARGS="$SCRAPER_ARGS $1 $2"
             shift 2
             ;;
+        --keep)
+            KEEP_ARG="--keep $2"
+            shift 2
+            ;;
         *)
             echo "Unknown argument: $1"
             echo ""
@@ -103,7 +112,7 @@ python3 merge_and_map.py || { echo -e "${RED}✗ Merge selhal${NC}"; FAILED=$((F
 
 END_EPOCH=$(date +%s)
 DURATION=$((END_EPOCH - START_EPOCH))
-python3 generate_status.py "$START_TIME" "$DURATION" "$LOG_FILE"
+python3 generate_status.py --start-time "$START_TIME" --duration "$DURATION" $KEEP_ARG
 
 echo ""
 echo "============================================================"