feat(viewer): v5 grid 2x2 + datebar calendar + mission label

- NAV viewer v5: grid 2x2 (map + charts), trail slider, play, layer toggles
- Datebar: date picker + datalist, fetches /api/data-dates from :8766
- Mission label shows #NN-folder (X sessions) in green or grey
- Tools: parse_usv_nav, extract_mcap_signals, extract_usv_pwm, merge_nav_usbl, usbl_to_json, check_sync, parse_kogger_usbl
- Vendor: Kogger-Protocol docs

tools/extract_usv_pwm.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+"""Extract USV PWM signals from navigation log CSVs."""
+import argparse, csv, glob, json, os, re, sys
+from datetime import datetime, timezone
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--nav-dir', required=True)
+    args = parser.parse_args()
+
+    pattern = os.path.join(args.nav_dir, '*_navigation_log.csv')
+    csv_files = sorted(glob.glob(pattern))
+    if not csv_files:
+        print(f"No navigation_log.csv in {args.nav_dir}", file=sys.stderr)
+        sys.exit(1)
+    print(f"Found {len(csv_files)} nav CSV files")
+
+    M_data = {}
+    RC_data = {}
+
+    for csv_file in csv_files:
+        print(f"  Parsing {os.path.basename(csv_file)}")
+        try:
+            with open(csv_file, 'r') as f:
+                reader = csv.DictReader(f)
+                for row in reader:
+                    ts_str = row.get('timestamp', '').strip()
+                    data = row.get('data', '').strip()
+                    val_str = row.get('value', '').strip()
+                    if not ts_str or not data or not val_str:
+                        continue
+                    is_M = re.match(r'^M\d+$', data)
+                    is_RC = re.match(r'^RC\d+$', data)
+                    if not is_M and not is_RC:
+                        continue
+                    try:
+                        val = float(val_str)
+                    except ValueError:
+                        continue
+                    try:
+                        dt = datetime.strptime(ts_str, '%Y-%m-%d %H:%M:%S.%f')
+                    except ValueError:
+                        try:
+                            dt = datetime.strptime(ts_str, '%Y-%m-%d %H:%M:%S')
+                        except ValueError:
+                            continue
+                    # CET -> UTC: subtract 3600s
+                    t_ms = int(dt.timestamp() * 1000) - 3600 * 1000
+                    pt = {'t': t_ms, 'v': val}
+                    if is_M:
+                        M_data.setdefault(data, []).append(pt)
+                    else:
+                        RC_data.setdefault(data, []).append(pt)
+        except Exception as e:
+            print(f"  Error {csv_file}: {e}")
+
+    all_t = []
+    for pts in list(M_data.values()) + list(RC_data.values()):
+        all_t.extend(p['t'] for p in pts)
+    t_min = min(all_t) if all_t else 0
+    t_max = max(all_t) if all_t else 0
+
+    for k in sorted(M_data):
+        print(f"  {k}: {len(M_data[k])} pts")
+    for k in sorted(RC_data):
+        print(f"  {k}: {len(RC_data[k])} pts")
+
+    fmt = lambda ms: datetime.fromtimestamp(ms/1000, tz=timezone.utc).isoformat()
+    print(f"t_min UTC: {fmt(t_min)}")
+    print(f"t_max UTC: {fmt(t_max)}")
+
+    out = {
+        'tz_assumed': 'CET (UTC+1)',
+        'tz_converted_to': 'UTC',
+        't_min_utc_ms': t_min,
+        't_max_utc_ms': t_max,
+        'M': M_data,
+        'RC': RC_data,
+    }
+
+    outdir = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'output')
+    os.makedirs(outdir, exist_ok=True)
+    outpath = os.path.join(outdir, 'usv_pwm.json')
+    with open(outpath, 'w') as f:
+        json.dump(out, f)
+    print(f"Written: {outpath}")
+
+if __name__ == '__main__':
+    main()