Add time zone config docs

docs/guides/administration/.pages

@@ -8,6 +8,7 @@ nav:
   - configuring-secret-management.md
   - configuring-internal-ca.md
   - configuring-http-proxy.md
+  - configuring-timezone.md
   - configuring-vulnerability-sources.md
   - running-air-gapped.md
   - configuring-observability.md

docs/guides/administration/configuring-timezone.md

@@ -0,0 +1,41 @@
+# Configuring the time zone
+
+!!! note
+    Running the API server with a non-UTC time zone requires Dependency-Track **5.0.1 or newer**.
+    Version 5.0.0 implicitly assumes UTC and misbehaves under any other zone.
+
+Dependency-Track does all internal date and time work in UTC, and the official container images set `TZ=Etc/UTC` to
+match. `TZ` is the standard POSIX environment variable for the system time zone. Setting it to a non-UTC value only
+changes how log timestamps render in the API server's `stdout` and `stderr`. Stored data, dashboards, policies, and REST
+responses stay UTC.
+
+!!! tip
+    Run the API server in UTC where you can. Log lines, partition names, and dashboard buckets correlate more easily
+    when they share a single zone.
+
+## Setting `TZ`
+
+Set `TZ` as an environment variable on the API server container:
+
+```yaml linenums="1" title="docker-compose.yaml"
+services:
+  apiserver:
+    image: dependencytrack/apiserver
+    environment:
+      TZ: "Europe/Paris"
+```
+
+Use any [IANA time zone identifier][iana-tz]. The container image ships with `tzdata`, so all identifiers resolve.
+
+## Database session time zone
+
+The API server's PostgreSQL sessions inherit `TZ`. This does not affect stored data. Writes go in as absolute instants,
+and partition maintenance and materialised view refreshes pin the session to UTC for their transactions.
+
+!!! warning
+    When connecting to the database directly, match your session zone to the API server's `TZ`. PostgreSQL renders
+    `timestamptz` in the session zone, interprets unqualified date and timestamp literals in it, and casts comparisons
+    through it. A mismatch makes the same row appear to shift by hours when reading, and silently inserts the wrong
+    instant when writing. Issue `SET TimeZone TO '<zone>'` before running ad-hoc updates.
+
+[iana-tz]: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones