feat(coder): complete orchestrator advanced patterns

- Approval gate steps pause and await human resolution
- appendStepEvent wired into markStep, failRun, dispatchAgentStep
- Trigger rule unit tests (6 variants)
- New parallel-research flow with one_success trigger

apps/coder/src/conductor/flows/parallel-research.ts

@@ -0,0 +1,59 @@
+import type { Flow, Step, StepContext } from '../types.js';
+
+const q = (ctx: StepContext) => String(ctx.input.question);
+
+/**
+ * Parallel research flow — dispatches 3 research agents simultaneously,
+ * then synthesizes the result on the first one to complete.
+ */
+export const parallelResearch: Flow = {
+  name: 'parallel-research',
+  description: 'Research from 3 angles in parallel, synthesize results on first completion',
+  steps: [
+    {
+      id: 'angle-web',
+      kind: 'agent',
+      agent: 'research-analyst',
+      run: (ctx) =>
+        `Research the following question from a web / prior-art perspective:\n\n${q(ctx)}`,
+    },
+    {
+      id: 'angle-code',
+      kind: 'agent',
+      agent: 'codebase-explorer',
+      deps: [],
+      run: (ctx) =>
+        `Research the following question from a codebase analysis perspective:\n\n${q(ctx)}`,
+    },
+    {
+      id: 'angle-security',
+      kind: 'agent',
+      agent: 'adversarial-security-analyst',
+      deps: [],
+      run: (ctx) =>
+        `Research the following question from a security perspective:\n\n${q(ctx)}`,
+    },
+    {
+      id: 'synthesize',
+      kind: 'code',
+      deps: ['angle-web', 'angle-code', 'angle-security'],
+      trigger_rule: 'one_success',
+      run: (ctx) => {
+        const web = ctx.results['angle-web'];
+        const code = ctx.results['angle-code'];
+        const security = ctx.results['angle-security'];
+        const parts = [
+          '# Parallel Research Synthesis',
+          '',
+          web ? `## Web Angle\n${web}` : '## Web Angle\n*(not yet completed)*',
+          code ? `## Code Angle\n${code}` : '## Code Angle\n*(not yet completed)*',
+          security ? `## Security Angle\n${security}` : '## Security Angle\n*(not yet completed)*',
+        ];
+        return parts.join('\n\n');
+      },
+    },
+  ],
+  render: (ctx) => {
+    return ctx.results['synthesize'] ?? 'No synthesis produced.';
+  },
+};