WIP: local handoff implementation

Local work on the social.io handoff before merging the claude
worktree branch. Includes the full per-spec Sources/Core/Design
module (8 files), watchOS target under WatchApp/, Live Activity +
widget extension, entitlements, scheme, and asset catalog.

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

swift/Sources/Core/Design/LaneChip.swift

@@ -0,0 +1,24 @@
+import SwiftUI
+
+struct LaneChip: View {
+    let lane: Lane
+    var count: Int?
+
+    var body: some View {
+        HStack(spacing: 5) {
+            Circle()
+                .fill(lane.color)
+                .frame(width: 7, height: 7)
+            Text(lane.label.uppercased())
+            if let count {
+                Text(count, format: .number)
+                    .foregroundStyle(lane.color.opacity(0.8))
+            }
+        }
+        .font(.caption2.weight(.semibold))
+        .padding(.horizontal, 9)
+        .padding(.vertical, 5)
+        .background(lane.color.opacity(0.14), in: RoundedRectangle(cornerRadius: SIO.chipRadius, style: .continuous))
+        .foregroundStyle(lane.color)
+    }
+}