docs: say the area breakdowns reach MCP clients only

Voice leaves aircraft_in_area and vessels_in_area out, so the changelog no
longer suggests spoken questions gain breakdowns. It also stops leading with
operators, which the default civil feed never reports.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

CHANGELOG.md

@@ -1,9 +1,10 @@
 # Changelog
 
-- `aircraft_in_area` and `vessels_in_area` take `group_by` and `stats`, so a
+- `aircraft_in_area` and `vessels_in_area` take `group_by` and `stats`, so an
-  client can ask which operators or ship types dominate an area, or the average
+  MCP client can ask which countries, aircraft types or ship types dominate an
-  altitude or speed, over every match instead of estimating from the returned
+  area, or the average altitude or speed, over every match instead of
-  rows.
+  estimating from the returned rows. Operator and type are counted only where
+  the feed reports them.
 
 - Treat explicitly current, complete empty vessel coverage as a successful update,
   clearing obsolete contacts while retaining stale or incomplete snapshots.

docs/CURRENT-STATE.md

@@ -98,7 +98,8 @@ count every match by a field (`group_by`: operator, country or type for
 aircraft; type or destination for ships; the ten largest groups, then other and
 unknown counts; the summary says when a feed reports none of the field) and
 summarize airborne altitude and speed (`stats`: count, min, median, mean, max).
-Both cover all matches, not just the rows returned. Voice offers the same queries next to its app
+Both cover all matches, not just the rows returned; voice leaves these two
+tools out, so they reach MCP clients only. Voice offers the same queries next to its app
 actions: the session lists them, and the browser runs them through the same
 catalog, loaded on first use. See [tools and the MCP server](TOOLS.md).