revert(cockpit): no water read timeout, and loaded reads not raise-only

Both reviews of the timeout found that Cesium cannot cancel a full-detail
read: each one given up kept its nine picks traversing every frame, so
stalled tiles piled up a new set every 30 s, while slow but valid answers
were dropped. Raise-only loaded reads then locked in a wrong-high height.
Back to one full-detail read at a time whose answer always applies, and
loaded reads that may adjust a river height but never take it to the sea;
a coarse probe can again lower it partway until the full read lands.

Keeps the test for another ship selected inside the double-click memory,
and corrects CURRENT-STATE: a failed read keeps the height it had.

docs/CURRENT-STATE.md

@@ -1574,10 +1574,9 @@ the full-detail read replaces it; it repeats every 5 s. Only one full-detail
 read runs at a time: while one is still running, a refresh reads the loaded
 tiles instead, and the slow read applies whenever it lands. Once a
 full-detail read has answered, loaded-tile reads no longer change the height;
-before then they may only raise it. A read that sampled nothing keeps the
-height it had, and a full-detail read still running after 30 s
-(`VESSEL_WATERLINE_READ_TIMEOUT_MS`) is given up for a fresh one. A failed read keeps
-the sea surface.
+before then they may find raised water but never take it back to the sea.
+A read that sampled nothing, or failed, keeps the height it had and is
+tried again on the next refresh.
 
 The HUD keeps its frame, vision styles, briefing, weather and Display/Radio
 utilities. It names the ship, reads `{type} · LIVE AIS · EYE {height}`, shows