feat(#92): implement Aggregated Dashboard View

Implement unified dashboard to display tasks and events from multiple
federated Mosaic Stack instances with clear provenance indicators.

Backend Integration:
- Extended federation API client with query support (sendFederatedQuery)
- Added query message fetching functions
- Integrated with existing QUERY message type from Phase 3

Components Created:
- ProvenanceIndicator: Shows which instance data came from
- FederatedTaskCard: Task display with provenance
- FederatedEventCard: Event display with provenance
- AggregatedDataGrid: Unified grid for multiple data types
- Dashboard page at /federation/dashboard

Key Features:
- Query all ACTIVE federated connections on load
- Display aggregated tasks and events in unified view
- Clear provenance indicators (instance name badges)
- PDA-friendly language throughout (no demanding terms)
- Loading states and error handling
- Empty state when no connections available

Technical Implementation:
- Uses POST /api/v1/federation/query to send queries
- Queries each connection for tasks.list and events.list
- Aggregates responses with provenance metadata
- Handles connection failures gracefully
- 86 tests passing with >85% coverage
- TypeScript strict mode compliant
- ESLint compliant

PDA-Friendly Design:
- "Unable to reach" instead of "Connection failed"
- "No data available" instead of "No results"
- "Loading data from instances..." instead of "Fetching..."
- Calm color palette (soft blues, greens, grays)
- Status indicators: 🟢 Active, 📋 No data, ⚠️ Error

Files Added:
- apps/web/src/lib/api/federation-queries.ts
- apps/web/src/lib/api/federation-queries.test.ts
- apps/web/src/components/federation/types.ts
- apps/web/src/components/federation/ProvenanceIndicator.tsx
- apps/web/src/components/federation/ProvenanceIndicator.test.tsx
- apps/web/src/components/federation/FederatedTaskCard.tsx
- apps/web/src/components/federation/FederatedTaskCard.test.tsx
- apps/web/src/components/federation/FederatedEventCard.tsx
- apps/web/src/components/federation/FederatedEventCard.test.tsx
- apps/web/src/components/federation/AggregatedDataGrid.tsx
- apps/web/src/components/federation/AggregatedDataGrid.test.tsx
- apps/web/src/app/(authenticated)/federation/dashboard/page.tsx
- docs/scratchpads/92-aggregated-dashboard.md

Testing:
- 86 total tests passing
- Unit tests for all components
- Integration tests for API client
- PDA-friendly language verified
- TypeScript type checking passing
- ESLint passing

Ready for code review and QA testing.

Related Issues:
- Depends on #85 (FED-005: QUERY Message Type) - COMPLETED
- Depends on #91 (FED-008: Connection Manager UI) - COMPLETED
- Uses #90 (FED-007: EVENT Subscriptions) infrastructure

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/web/src/components/federation/ProvenanceIndicator.test.tsx

@@ -0,0 +1,105 @@
+/**
+ * ProvenanceIndicator Component Tests
+ */
+
+import { describe, it, expect } from "vitest";
+import { render, screen } from "@testing-library/react";
+import { ProvenanceIndicator } from "./ProvenanceIndicator";
+
+describe("ProvenanceIndicator", () => {
+  it("should render instance name", () => {
+    render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+      />
+    );
+
+    expect(screen.getByText("Work Instance")).toBeInTheDocument();
+  });
+
+  it("should render with compact mode", () => {
+    const { container } = render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+        compact={true}
+      />
+    );
+
+    // Compact mode should have smaller padding
+    const badge = container.querySelector(".px-2");
+    expect(badge).toBeInTheDocument();
+  });
+
+  it("should render with custom color", () => {
+    const { container } = render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+        color="bg-blue-100"
+      />
+    );
+
+    const badge = container.querySelector(".bg-blue-100");
+    expect(badge).toBeInTheDocument();
+  });
+
+  it("should render with default color when not provided", () => {
+    const { container } = render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+      />
+    );
+
+    const badge = container.querySelector(".bg-gray-100");
+    expect(badge).toBeInTheDocument();
+  });
+
+  it("should show tooltip with instance details on hover", () => {
+    render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+      />
+    );
+
+    // Check for title attribute (tooltip)
+    const badge = screen.getByText("Work Instance");
+    expect(badge.closest("div")).toHaveAttribute(
+      "title",
+      "From: Work Instance (https://mosaic.work.example.com)"
+    );
+  });
+
+  it("should render with icon when showIcon is true", () => {
+    render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+        showIcon={true}
+      />
+    );
+
+    expect(screen.getByText("🔗")).toBeInTheDocument();
+  });
+
+  it("should not render icon by default", () => {
+    render(
+      <ProvenanceIndicator
+        instanceId="instance-work-001"
+        instanceName="Work Instance"
+        instanceUrl="https://mosaic.work.example.com"
+      />
+    );
+
+    expect(screen.queryByText("🔗")).not.toBeInTheDocument();
+  });
+});