feat(ios): comprehensive iPhone+iPad UX polish — refined-native design system

Freeze a shared design system (DesignSystem/{Tokens,Typography,StatusStyle,
Primitives}.swift): indigo #7C8CFF accent (root .tint), semantic status colors,
2-4-8-12-16-20-24 spacing + sm8/md12/lg16 radii scale, SF Mono tabular numbers,
reduce-motion-gated animations, haptics, reusable StatusBadge/TelemetryChip/Card/
SectionHeader/DSButtonStyle/ContinueLastBanner. Every changed view consumes tokens
— no hardcoded colors/spacing.

Applied across all surfaces (visual only — zero behavior/logic change, all suites
green): session list rows + status system (shape+color, not color-alone) +
telemetry chips + thumbnail placeholders; terminal gate card (≥44pt approve/reject)
+ keybar + reconnect + quick-reply + digest + SwiftTerm accent theme; pairing hero
+ warning tiers + Projects cards + Timeline/Diff; nav chrome + iPad split placeholder
+ privacy shade + motion. Chinese gate copy. UX finding fixed: timeline class colors
now via DS.Palette (+timelineTool/timelineUser tokens).

Design review 8.5/10. Verified: iPhone 16 290 + iPad Pro 11 290 tests green;
packages + integration green; consistency audit ~clean; zero changes under
ios/Packages, src/, public/.

ios/App/WebTerm/Components/KeyBar.swift

@@ -95,12 +95,17 @@ enum KeyBarLayout {
     ]
 }
 
+/// Layout constants — all composed from the frozen `DS` scale (no literals).
+/// UIKit reads the same CGFloat tokens the SwiftUI chrome uses, so the key bar
+/// stays on-grid with the rest of the app.
 private enum KeyBarMetrics {
-    static let barHeight: CGFloat = 52
-    static let buttonSpacing: CGFloat = 6
-    static let contentInset: CGFloat = 8
+    /// A hit-target-tall row plus a little breathing room (44 + 8).
+    static let barHeight: CGFloat = DS.Layout.minHitTarget + DS.Space.sm8
+    static let buttonSpacing: CGFloat = DS.Space.xs4
+    static let contentInset: CGFloat = DS.Space.sm8
     static let buttonInsets = NSDirectionalEdgeInsets(
-        top: 4, leading: 9, bottom: 4, trailing: 9
+        top: DS.Space.xs4, leading: DS.Space.md12,
+        bottom: DS.Space.xs4, trailing: DS.Space.md12
     )
 }
 
@@ -172,7 +177,13 @@ final class KeyBarView: UIInputView {
     }
 
     private func makeButton(for spec: KeyBarButtonSpec) -> UIButton {
-        var config: UIButton.Configuration = spec.isPrimary ? .tinted() : .plain()
+        // Keycap look: primary (Esc) wears the accent tint, the rest a subtle
+        // gray fill; both get an sm8 rounded corner. (`.secondaryLabel` is the
+        // UIKit twin of DS.Palette.textSecondary — the DS UIColor surface only
+        // vends the accent, so native system labels stand in at this boundary.)
+        var config: UIButton.Configuration = spec.isPrimary ? .tinted() : .gray()
+        config.cornerStyle = .fixed
+        config.background.cornerRadius = DS.Radius.sm8
         var label = AttributedString(spec.label)
         label.font = UIFont.monospacedSystemFont(
             ofSize: UIFont.preferredFont(forTextStyle: .footnote).pointSize,
@@ -187,7 +198,14 @@ final class KeyBarView: UIInputView {
         config.contentInsets = KeyBarMetrics.buttonInsets
 
         let button = UIButton(configuration: config)
+        if spec.isPrimary {
+            button.tintColor = DS.Palette.accentUIColor()
+        }
         button.accessibilityLabel = spec.title
+        // HIG minimum touch target regardless of glyph width.
+        button.heightAnchor
+            .constraint(greaterThanOrEqualToConstant: DS.Layout.minHitTarget)
+            .isActive = true
         button.addAction(
             UIAction { [weak self] _ in self?.onKey?(spec.key) },
             for: .touchUpInside