Translate the new Selection labels, and pin what SELECTIONPREVIEW's bits do

The ten strings the Options card gained were English in nineteen of the
twenty-one locales. They are now translated in all of them, using the words
each locale already uses for the surrounding labels — de-DE "Griffe",
fr-FR "Poignées", zh-CN "夹点", zh-TW "掣點" and so on for grips, and the
same for selection, preview and object. System-variable names stay in Latin
uppercase, as they already do in every locale's SETVAR listing.

Composing them from existing keys, the way el-GR composes the neighbouring
labels, only worked for one of the ten: there is no existing key for "limit",
"unlimited", "shift", "rectangle" or "lasso", and "Grips: Objects" as the
label of a numeric limit would read worse than English.

The rollover preview was reported as possibly not working. It works, and now
says so: `the_idle_rollover_follows_bit_one` drives a settled hover over a
line and checks what the scene highlighted, for all four values of the
bitmask. Bit 1 alone highlights, bit 2 alone does not, both do, neither does
not. That is the assertion the inverted config comment would have made
someone doubt — the pick simply needs the cursor still for the 500 ms of
`HOVER_DWELL_MS` before it runs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

locales/cs-CZ/opencadstudio.ftl

@@ -1375,16 +1375,16 @@ common =
     .pick-box-size = { common.pickbox }: { common.size }
     .controls-both-the-visible-selection-box-and-the-click-aperture = Ovládá viditelný výběrový rámeček i oblast kliknutí.
     .visual-effect-settings = { common.visual-effects } · { properties.settings }
-    .selection-modes = Selection Modes
-    .use-shift-to-add-to-selection-pickadd = Use Shift to add to selection (PICKADD)
-    .press-and-drag-draws-a-rectangle-instead-of-a-lasso-pickdrag = Press and drag draws a rectangle instead of a lasso (PICKDRAG)
-    .show-selection-effect-selectioneffect = Show selection effect (SELECTIONEFFECT)
-    .preview-selection-when-no-command-is-active = Preview selection when no command is active
-    .preview-selection-during-a-command = Preview selection during a command
-    .highlights-the-object-under-the-cursor-before-it-is-picked-selectionpreview = Highlights the object under the cursor before it is picked (SELECTIONPREVIEW).
-    .object-limit-for-grips = Object limit for grips
-    .unlimited = Unlimited
-    .past-this-many-selected-objects-no-grips-are-drawn-0-removes-the-limit-gripobjlimit = Past this many selected objects no grips are drawn; 0 removes the limit (GRIPOBJLIMIT).
+    .selection-modes = Režimy výběru
+    .use-shift-to-add-to-selection-pickadd = Použít Shift pro přidání do výběru (PICKADD)
+    .press-and-drag-draws-a-rectangle-instead-of-a-lasso-pickdrag = Tažení kreslí obdélník místo lasa (PICKDRAG)
+    .show-selection-effect-selectioneffect = Zobrazit efekt výběru (SELECTIONEFFECT)
+    .preview-selection-when-no-command-is-active = Náhled výběru, když není aktivní žádný příkaz
+    .preview-selection-during-a-command = Náhled výběru během příkazu
+    .highlights-the-object-under-the-cursor-before-it-is-picked-selectionpreview = Zvýrazní objekt pod kurzorem před jeho výběrem (SELECTIONPREVIEW).
+    .object-limit-for-grips = Limit objektů pro uzly
+    .unlimited = Bez omezení
+    .past-this-many-selected-objects-no-grips-are-drawn-0-removes-the-limit-gripobjlimit = Nad tímto počtem vybraných objektů se uzly nekreslí; 0 limit ruší (GRIPOBJLIMIT).
     .indicate-selection-area-with-transparent-fill-selectionarea = Zobrazit oblast výběru průhlednou výplní (SELECTIONAREA)
     .selection-area-opacity = { common.selection }: { properties.opacity }
     .transparency-of-the-window-and-crossing-selection-areas-selectionareaopacity = Průhlednost oblastí výběru oknem a křížením (SELECTIONAREAOPACITY).