Agent workspaces: per-contract overlays with instant handoff

- WorkspaceManager: create/get/list workspaces with daily/weekly/monthly/pinned tiers
- Saved searches: agent stores SQL queries in workspace context
- Shortlist: tag candidates/records to a workspace with notes
- Activity log: track calls, emails, updates per workspace per agent
- Instant handoff: transfer workspace ownership with full history
  Zero data copy — just a pointer swap, receiving agent sees everything
- Persistence: workspaces stored as JSON in object storage, rebuilt on startup
- Endpoints: /workspaces/create, /{id}, /{id}/handoff, /{id}/search,
  /{id}/shortlist, /{id}/activity
- Tested: Sarah creates workspace, saves searches, shortlists 3 candidates,
  logs activity, hands off to Mike who continues seamlessly

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

data/workspaces/ws-1774619041730.json

@@ -0,0 +1,40 @@
+{
+  "id": "ws-1774619041730",
+  "name": "Apex Corp - .NET Developers Chicago",
+  "description": "Fill 5 .NET developer positions for Apex Corp, downtown Chicago, $65-85/hr bill rate",
+  "tier": "weekly",
+  "owner": "Sarah",
+  "previous_owners": [],
+  "created_at": "2026-03-27T13:44:01.730143708Z",
+  "updated_at": "2026-03-27T13:44:08.530268827Z",
+  "saved_searches": [
+    {
+      "name": "Chicago .NET active candidates",
+      "sql": "SELECT candidate_id, first_name, last_name, phone, email, years_experience FROM candidates WHERE city = 'Chicago' AND skills LIKE '%.NET%' AND status = 'active' ORDER BY years_experience DESC",
+      "created_at": "2026-03-27T13:44:01.731891844Z"
+    },
+    {
+      "name": "test",
+      "sql": "SELECT 1",
+      "created_at": "2026-03-27T13:44:08.530262069Z"
+    }
+  ],
+  "shortlist": [],
+  "activity": [
+    {
+      "action": "search",
+      "detail": "saved search: Chicago .NET active candidates",
+      "timestamp": "2026-03-27T13:44:01.731898474Z",
+      "agent": "Sarah"
+    },
+    {
+      "action": "search",
+      "detail": "saved search: test",
+      "timestamp": "2026-03-27T13:44:08.530268200Z",
+      "agent": "Sarah"
+    }
+  ],
+  "ingested_datasets": [],
+  "delta_keys": [],
+  "tags": []
+}