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/database/template-node-configs.test.ts

@@ -27,6 +27,18 @@ describe('Template Node Configs Database Integration', () => {
     const migrationPath = path.join(__dirname, '../../../src/database/migrations/add-template-node-configs.sql');
     const migration = fs.readFileSync(migrationPath, 'utf-8');
     db.exec(migration);
+
+    // Insert test templates with id 1-1000 to satisfy foreign key constraints
+    // Tests insert configs with various template_id values, so we pre-create many templates
+    const stmt = db.prepare(`
+      INSERT INTO templates (
+        id, workflow_id, name, description, views,
+        nodes_used, created_at, updated_at
+      ) VALUES (?, ?, ?, ?, ?, ?, datetime('now'), datetime('now'))
+    `);
+    for (let i = 1; i <= 1000; i++) {
+      stmt.run(i, i, `Test Template ${i}`, 'Test template for node configs', 100, '[]');
+    }
   });
 
   afterEach(() => {
@@ -242,14 +254,7 @@ describe('Template Node Configs Database Integration', () => {
     beforeEach(() => {
       // Enable foreign keys
       db.exec('PRAGMA foreign_keys = ON');
-
-      // Create a template first
-      db.prepare(`
-        INSERT INTO templates (
-          id, workflow_id, name, description, views,
-          nodes_used, created_at, updated_at
-        ) VALUES (?, ?, ?, ?, ?, ?, datetime('now'), datetime('now'))
-      `).run(1, 100, 'Test Template', 'Description', 500, '[]');
+      // Note: Templates are already created in the main beforeEach
     });
 
     it('should allow inserting config with valid template_id', () => {