refactor(design): lock the border-radius ladder, one radius per role (#1607)

Seven radii were in circulation (4/5/6/8/12/16px + pill) with no rule for
which went where; one toolbar row on /transactions mixed four shape
languages. This locks a 4-tier ladder (design.md convention 16):

- pill: interactive toolbar controls (buttons, chips, pickers, segmented
  controls, toolbar search, count nubs)
- rounded-xl (12px): overlay tier: page panel, dialogs, slide-overs
- rounded-lg (8px): cards, form fields, popover/menu content, boxes
- rounded-sm (4px): nested leaves (menu items, checkboxes, kbd/code nubs)

Changes:
- New SegmentedControl primitive (pill-in-pill tablist, h-8) replaces the
  hand-rolled bg-muted/70 tablist copied across 11 files
- New ToolbarSearch primitive (pill, h-8) adopted on 9 page toolbars;
  dialog/picker searches keep the rounded-lg Input
- dialog.tsx 8px -> 12px, matching SettingsModal/slide-over/CommandPalette
- ContextPicker chips at the shared h-8 toolbar height
- ~300 rounded-md / bare rounded call sites remapped by role; auth icon
  tiles and the mobile nav sheet come down from 16px to 12px
- rounded-md, bare rounded, rounded-2xl and rounded-[Npx] are dead
  vocabulary, enforced by a new off-ladder-radius check in check:guards

Verified: lint 0 errors, 14422 unit tests pass, check:guards green, tsc
clean on all changed files, sandbox screenshots of transactions/
bookkeeping/granskning toolbars and the Ny verifikation dialog.

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

components/dimensions/DimensionCombobox.tsx

@@ -265,7 +265,7 @@ export default function DimensionCombobox({
       {isOpen && !disabled && (
         <div
           ref={listRef}
-          className="absolute z-50 top-full left-0 mt-1 min-w-[16rem] w-[max(100%,20rem)] max-h-[300px] overflow-y-auto rounded-md border border-input bg-card shadow-md"
+          className="absolute z-50 top-full left-0 mt-1 min-w-[16rem] w-[max(100%,20rem)] max-h-[300px] overflow-y-auto rounded-lg border border-input bg-card shadow-md"
         >
           {loadState === 'loading' && (
             <div className="flex items-center gap-2 px-2 py-2 text-sm text-muted-foreground">

components/dimensions/DimensionsManager.tsx

@@ -6,6 +6,8 @@ import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
 import { Input } from '@/components/ui/input'
 import { Label } from '@/components/ui/label'
+import { SegmentedControl } from '@/components/ui/segmented-control'
+import { ToolbarSearch } from '@/components/ui/toolbar-search'
 import { Skeleton } from '@/components/ui/skeleton'
 import { Switch } from '@/components/ui/switch'
 import { TH_CLASS, TD_CLASS, QUIET_LINK_CLASS } from '@/components/ui/dry-table'
@@ -368,40 +370,30 @@ export default function DimensionsManager() {
           muted value count, search, and the actions far right. */}
       <div className="space-y-2">
         <div className="flex flex-wrap items-center gap-2">
-          <div className="inline-flex shrink-0 gap-0.5 rounded-lg bg-muted/70 p-[3px]" role="tablist">
-            {dimensions.map((dim) => (
-              <button
-                key={dim.id}
-                type="button"
-                role="tab"
-                aria-selected={activeDimId === dim.id}
-                onClick={() => {
-                  setActiveDimId(dim.id)
-                  setSearchTerm('')
-                }}
-                className={cn(
-                  'inline-flex items-center gap-1.5 rounded-md px-3.5 py-[5px] text-[12.5px] transition-colors duration-150',
-                  activeDimId === dim.id
-                    ? 'border border-border bg-card font-medium text-foreground'
-                    : 'text-muted-foreground hover:text-foreground',
-                )}
-              >
-                {dim.name}
-                {dim.values.length > 0 && (
-                  <span className="text-muted-foreground tabular-nums">{dim.values.length}</span>
-                )}
-              </button>
-            ))}
-          </div>
-          <div className="relative min-w-[180px] max-w-xs flex-1">
-            <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
-            <Input
-              placeholder={t('search_placeholder')}
-              value={searchTerm}
-              onChange={(e) => setSearchTerm(e.target.value)}
-              className="h-9 pl-10"
-            />
-          </div>
+          <SegmentedControl
+            value={activeDimId ?? ''}
+            onChange={(id) => {
+              setActiveDimId(id)
+              setSearchTerm('')
+            }}
+            options={dimensions.map((dim) => ({
+              value: dim.id,
+              label: (
+                <>
+                  {dim.name}
+                  {dim.values.length > 0 && (
+                    <span className="text-muted-foreground tabular-nums">{dim.values.length}</span>
+                  )}
+                </>
+              ),
+            }))}
+          />
+          <ToolbarSearch
+            placeholder={t('search_placeholder')}
+            value={searchTerm}
+            onChange={(e) => setSearchTerm(e.target.value)}
+            containerClassName="min-w-[180px] max-w-xs flex-1"
+          />
           <div className="ml-auto flex items-center gap-4">
             <button
               type="button"