fix(tests): resolve foreign key constraints and remove get_node_for_task from integration tests

Two critical fixes for integration test failures:

**1. Foreign Key Constraint Violations**
Root cause: Tests inserted into template_node_configs without corresponding
entries in templates table, causing FK constraint failures.

Fixes:
- template-node-configs.test.ts: Pre-create 1000 test templates in beforeEach()
- template-examples-e2e.test.ts: Create templates in seedTemplateConfigs() and
  adjust test cases to use non-conflicting template IDs

**2. Removed Tool References**
Root cause: Tests referenced get_node_for_task tool removed in v2.15.0.

Fixes:
- tool-invocation.test.ts: Removed entire get_node_for_task test suite
- session-management.test.ts: Replaced get_node_for_task test with search_nodes

Test results:
✅ template-node-configs.test.ts: 20/20 passed
✅ template-examples-e2e.test.ts: 13/13 passed
✅ tool-invocation.test.ts: 28/28 passed
✅ session-management.test.ts: 16 passed, 2 skipped

All integration tests now comply with foreign key constraints and use only
existing MCP tools as of v2.15.0.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

tests/integration/mcp-protocol/session-management.test.ts

@@ -483,10 +483,11 @@ describe('MCP Session Management', { timeout: 15000 }, () => {
       await client.connect(clientTransport);
 
       // Multiple error-inducing requests
+      // Note: get_node_for_task was removed in v2.15.0
       const errorPromises = [
         client.callTool({ name: 'get_node_info', arguments: { nodeType: 'invalid1' } }).catch(e => e),
         client.callTool({ name: 'get_node_info', arguments: { nodeType: 'invalid2' } }).catch(e => e),
-        client.callTool({ name: 'get_node_for_task', arguments: { task: 'invalid_task' } }).catch(e => e)
+        client.callTool({ name: 'search_nodes', arguments: { query: '' } }).catch(e => e) // Empty query should error
       ];
 
       const errors = await Promise.all(errorPromises);