feat(workflows): replace basic templates with 8 rich hand-crafted templates

Replace auto-generated pattern-based templates with complex, real-world
workflow templates showcasing all node types and edge features:

- Code Review Pipeline: sequential chain with checkpointing
- Research & Summarize: 3 parallel agents via fan-out/fan-in
- Customer Support Triage: conditional routing with expression edges
- Content Creation Pipeline: writer/editor revision loop
- Multi-Agent Debate: proposer/critic debate loop
- Data Processing with Validation: invoke-function nodes, state scopes
- Approval Workflow: request-port for human-in-the-loop review
- Nested Workflow Orchestrator: inline sub-workflow composition

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/shared/workspace.test.ts

@@ -31,11 +31,14 @@ describe('workspace seed', () => {
       'magentic',
     ]);
     expect(workspace.workflowTemplates.map((template) => template.id)).toEqual([
-      'workflow-template-single',
-      'workflow-template-sequential',
-      'workflow-template-concurrent',
-      'workflow-template-handoff',
-      'workflow-template-group-chat',
+      'workflow-template-code-review',
+      'workflow-template-research-summarize',
+      'workflow-template-customer-support',
+      'workflow-template-content-creation',
+      'workflow-template-multi-agent-debate',
+      'workflow-template-data-processing',
+      'workflow-template-approval',
+      'workflow-template-nested-orchestrator',
     ]);
 
     for (const pattern of workspace.patterns) {