test: check the route cap at exactly 200 turns

The existing "route that fits" case used 199 steps, which is how the
off-by-one went unnoticed. Folds the docs note into the existing cap sentence
and makes the changelog entry specific.

docs/CURRENT-STATE.md

@@ -3327,10 +3327,6 @@ from fixtures (`providers/mapillary/coverageFixture.mjs`,
 photo flow. CI runs the fixture gate and `qa:panel-resize`
 against a production build served by `vite preview` with a dummy token.
 
-Directions retains up to 200 turn instructions. Its truncation notice appears
-only when another independent instruction is omitted; a complete route with
-exactly 200 turns does not show the notice.
-
 Directions is a keyless front end to the routing the voice agent already
 uses. Its row chips are the whole interface: DRIVE / WALK / BIKE pick the
 profile; SET A and SET B arm the next globe click (Escape or a second press
@@ -3403,9 +3399,10 @@ rate limit from the routing service is reported as one instead of as "no route
 found". `src/data/routeSteps.js` turns OSRM maneuver type / modifier / exit /
 road name into one plain-English sentence per decision, folding
 `exit roundabout` steps into the roundabout they leave, and caps one route at
-200 maneuvers — a route past that cap is reported as cut off, in the row
-summary and as the last line of the list, because the arrival step is among
-the ones dropped.
+200 maneuvers — a route with more is reported as cut off, in the row summary
+and as the last line of the list, because the arrival step is among the ones
+dropped. A route of exactly 200 is complete, and a roundabout exit after the
+200th keeps folding into it.
 
 A step's card opens from its dot on the globe or from its line in the list, and
 the list covers every step including departure and arrival, which have no dot.