Architecture diagram: version 2 from the project

Replaces the diagram with the corrected version 2 (title without commit
hash, Query with the from/to zoom bounds, Histogram box linked to the API
and VictoriaLogs, arrow labels on a white background), and adds a
Timeline bullet to the README legend.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

README.md

@@ -18,8 +18,9 @@ devices ──514 udp/tcp──▶ logstream (Go) ──HTTP batches──▶ Vi
   on IP hosts), then the `Store` queue, which sends them in batches to VictoriaLogs.
 - **Live view**: `sink()` also publishes each message to the `Hub`, which streams it to the
   browsers over SSE.
-- **Search**: the HTTP API turns the UI filters into LogsQL queries sent to VictoriaLogs;
-  `histogram.go` computes the timeline intervals (division, time zone, count per severity).
+- **Search**: the HTTP API turns the UI filters into LogsQL queries sent to VictoriaLogs.
+- **Timeline**: `/api/histogram` (`histogram.go`) counts the logs per interval and severity,
+  aligned on the local time; the zoom bounds (`from`/`to`) also apply to the list and the export.
 - **State**: tags and source settings live in `/data` (`logstream-data` volume); the logs
   themselves in the `vlogs-data` volume.