Show every time in US Eastern (America/New_York)

Webapp: config.DISPLAY_TZ (default America/New_York) and a local_dt
filter that renders datetimes, ISO strings and Unix timestamps as e.g.
"2026-10-05 13:54 EDT", DST included. Used for the ServiceNow tick list,
technician to-do, imaging tiles and detail page; timestamp_fmt (reports,
backups, enrollment) goes through it too instead of relying on the
process TZ. CSV report_date is Eastern with its offset. Evidence-pack
months are Eastern calendar months, so a wipe late on the 31st lands in
that month rather than the next.

Blancco: init points the new root's /etc/localtime at America/New_York
so the GUI clock is local. Report timestamps keep their explicit
offset; report.utc_offset stays 0 since a fixed offset cannot follow DST.
Report file names stay UTC, as Blancco's own Save names them.

webapp/app.py

@@ -638,7 +638,7 @@ def blancco_export_reports():
         if when < since:
             continue
         rows.extend(blancco_report.export_rows(
-            f, data, when.isoformat(),
+            f, data, to_display_tz(when).isoformat(),
             blancco_evidence.cloud_status(cloud_state, (data.get("meta") or {}).get("document_id", ""))))
         files.append(f)
         pdf = os.path.splitext(f)[0] + ".pdf"
@@ -1490,10 +1490,40 @@ def api_save_unattend(image_type):
 # Template helpers
 # ---------------------------------------------------------------------------
 
+def to_display_tz(value):
+    """datetime (naive = UTC), ISO-8601 string or Unix timestamp -> aware
+    datetime in config.DISPLAY_TZ; None when it cannot be read."""
+    from datetime import timezone
+    from zoneinfo import ZoneInfo
+    if value is None or value == "":
+        return None
+    if isinstance(value, (int, float)):
+        dt = datetime.fromtimestamp(value, timezone.utc)
+    elif isinstance(value, datetime):
+        dt = value if value.tzinfo else value.replace(tzinfo=timezone.utc)
+    else:
+        try:
+            dt = datetime.fromisoformat(str(value).replace("Z", "+00:00"))
+        except ValueError:
+            return None
+        if not dt.tzinfo:
+            dt = dt.replace(tzinfo=timezone.utc)
+    return dt.astimezone(ZoneInfo(config.DISPLAY_TZ))
+
+
+@app.template_filter("local_dt")
+def local_dt(value, seconds=False):
+    """Any timestamp shown in the UI, as e.g. '2026-10-05 13:54 EDT'."""
+    dt = to_display_tz(value)
+    if dt is None:
+        return value or "-"
+    return dt.strftime("%Y-%m-%d %H:%M:%S %Z" if seconds else "%Y-%m-%d %H:%M %Z")
+
+
 @app.template_filter("timestamp_fmt")
 def timestamp_fmt(ts):
-    """Format a Unix timestamp to a human-readable date string."""
-    return datetime.fromtimestamp(ts).strftime("%Y-%m-%d %H:%M")
+    """Format a Unix timestamp in the display timezone."""
+    return local_dt(ts)
 
 
 @app.context_processor