feat(rundown): keep per-button hover tooltips on offset toggle

Restore the short per-mode hover tooltips on Absolute/Relative alongside
the in-pill info icon. The icon carries the side-by-side comparison; the
per-button tooltips give a quick reminder of the hovered mode and keep the
group consistent with the Run/Edit and List/Table toggles.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hj5P4eDgf97zSCzViGHNDy

apps/client/src/features/rundown/rundown-header/RundownHeader.tsx

@@ -109,12 +109,18 @@ function RundownHeader({ isExtracted, viewMode, setViewMode }: RundownHeaderProp
       {showOffsetToggle && (
         <div className={style.group}>
           <ToggleGroup value={[offsetMode]} onValueChange={toggleOffsetMode} className={style.segments}>
-            <Toolbar.Button render={<Toggle />} value={OffsetMode.Absolute} className={style.radioButton}>
+            <Tooltip
+              text='Offset measured against the scheduled clock time'
+              render={<Toolbar.Button render={<Toggle />} value={OffsetMode.Absolute} className={style.radioButton} />}
+            >
               Absolute
-            </Toolbar.Button>
+            </Tooltip>
-            <Toolbar.Button render={<Toggle />} value={OffsetMode.Relative} className={style.radioButton}>
+            <Tooltip
+              text='Offset measured from when the rundown actually started'
+              render={<Toolbar.Button render={<Toggle />} value={OffsetMode.Relative} className={style.radioButton} />}
+            >
               Relative
-            </Toolbar.Button>
+            </Tooltip>
           </ToggleGroup>
           <Tooltip
             text='Absolute measures offset against the scheduled clock time. Relative measures it from when the rundown actually started.'