fix: replace monospaced ALL CAPS labels with Inter sentence case

Remove IBM Plex Mono + text-transform: uppercase from all UI labels.
CSS classes .font-mono-label and .font-mono-overline now use Inter
with no text-transform. Inline monospace+uppercase styles in
StatusDropdown, TagsDropdown, ReferencedByPanel, AiActionCard replaced.
Tailwind uppercase removed from Sidebar, CommandPalette, PulseView,
CreateNoteDialog, CreateTypeDialog. Hardcoded ALL CAPS text (COLOR,
ICON, TEMPLATE) converted to sentence case. Code blocks and commit
hashes remain monospaced.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/PulseView.tsx

@@ -167,7 +167,7 @@ function DayGroup({ label, commits, onOpenNote }: {
         onClick={() => setCollapsed((v) => !v)}
       >
         <Chevron size={12} className="text-muted-foreground" />
-        <span className="text-[11px] font-semibold uppercase tracking-wider text-muted-foreground">
+        <span className="text-[11px] font-medium text-muted-foreground">
           {label}
         </span>
         <span className="text-[11px] text-muted-foreground">