feat(design): adopt ScarfDesign system across Mac UI

Add a typed design-system package (Packages/ScarfDesign) with rust-tone
color tokens, type scale, spacing/radius tokens, ScarfPageHeader and
component primitives (ScarfCard, ScarfBadge, ScarfTextField,
ScarfSectionHeader, ScarfDivider, four button styles). Both Mac and iOS
targets `import ScarfDesign`.

Sidebar redesigned per design/static-site/ui-kit/Sidebar.jsx — glassy
translucent background, 224 px width, app-icon header with server pill,
custom tokenized rows with rust accent-tint when active, footer with
live Hermes-running indicator (wired to ServerLiveStatusRegistry).

14 mockup-backed feature screens redesigned: Settings, Dashboard,
Sessions, Memory, Chat (visual sweep), Activity, Cron, Insights,
MCPServers, Health, Logs, Tools (full); Projects light-touch.
Non-mockup features inherit rust through AccentColor.colorset repoint.

Mac AppIcon.appiconset replaced with the rust set. AccentColor.colorset
repointed to BrandRust hex (light + dark variants).

Visual sweep: every multi-button page-header / action-bar cluster now
wraps in .fixedSize(horizontal: true, vertical: false) so labels can't
wrap letter-by-letter at narrow widths (regression seen on the MCP
detail pane with 4 buttons).

Follow-ups landed:
- Sidebar Hermes-running probe wired to per-window
  ServerLiveStatusRegistry (no more placeholder green).
- Sessions: today filter predicate (isDateInToday(startedAt)); pill
  count reflects real count. Starred stays a no-op pending an upstream
  pinned/starred field on HermesSession.
- Dashboard: Recent activity column rendered alongside Recent sessions
  in a ViewThatFits 2-col grid. Populated from
  HermesDataService.fetchRecentToolCalls(limit:) flattened to
  ActivityEntry. ActivityEntry gains a public memberwise init.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

design/Assets.xcassets/AppIcon-iOS.appiconset/Contents.json

@@ -0,0 +1,11 @@
+{
+  "images" : [
+    {
+      "filename" : "Scarf-AppIcon-iOS-1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : { "author" : "xcode", "version" : 1 }
+}