feat(FN-4367): add structured JSON verdict output for prompt-mode workflow steps

- Add verdict (PASS/FAIL) field to core WorkflowStepResult type
- Add parseWorkflowStepOutput() engine helper for json-workflow-verdict blocks
- Update executeWorkflowStep to extract structured verdict/notes from output
- Persist verdict and notes in runWorkflowSteps result entries
- Update agent prompt Feedback Format to require JSON verdict block
- Update WS-006 (Frontend UX Design) template prompt with structured fast-bail
- Add WorkflowResultsTab verdict badge and notes rendering with CSS
- Add 11 engine tests for verdict parsing edge cases
- Add 6 dashboard tests for verdict/notes rendering
- Create replace-ws006-prompt.mjs migration script for existing DBs
- Add changeset for @runfusion/fusion patch

Fusion-Task-Id: FN-4367
Fusion-Task-Lineage: adbfac60-5cfe-4ae9-9706-1094dfe7d676

scripts/replace-ws006-prompt.mjs

@@ -0,0 +1,110 @@
+#!/usr/bin/env node
+/**
+ * Replace the WS-006 (Frontend UX Design) workflow step prompt in the database
+ * with the updated version that uses structured JSON verdict output.
+ *
+ * Usage:
+ *   node scripts/replace-ws006-prompt.mjs [--db=.fusion/fusion.db] [--dry-run]
+ *
+ * Flags:
+ *   --db=<path>    Path to the SQLite database (default: .fusion/fusion.db)
+ *   --dry-run      Print the new prompt without writing to the database
+ *
+ * Idempotent: re-running replaces the prompt again with the same content.
+ */
+
+import Database from "better-sqlite3";
+import { resolve } from "node:path";
+
+const args = process.argv.slice(2);
+const dbArg = args.find((a) => a.startsWith("--db="));
+const dryRun = args.includes("--dry-run");
+const dbPath = dbArg ? dbArg.slice(5) : ".fusion/fusion.db";
+
+const NEW_PROMPT = `You are a UX design reviewer. Verify frontend changes maintain visual polish and consistency with existing UI patterns and design tokens.
+
+## Step 1: Scope Check (MANDATORY FIRST)
+
+The task harness provides a "Diff Scope" listing files this task actually changed.
+
+If the Diff Scope contains ZERO frontend/UI files (no .tsx/.jsx/.ts/.js component files, no .css/.scss/.sass/.styl, no .html/.vue/.svelte/.astro, no design-token/theme files), output ONLY:
+
+\`\`\`json-workflow-verdict
+{"verdict":"PASS","notes":"No UI changes in scope — approved."}
+\`\`\`
+
+Then STOP. Do not browse the worktree. Do not read any files.
+
+If there ARE frontend/UI files in scope, proceed to Step 2.
+
+## Step 2: Design Review
+
+Restrict your review to ONLY the UI files in the diff scope.
+
+Check:
+1. **Visual Hierarchy** — heading levels, content flow, information architecture
+2. **Spacing and Typography** — consistent margins, padding, gaps, type scale
+3. **Color and Token Consistency** — CSS custom properties and design tokens used; no hardcoded colors
+4. **Component Reuse** — existing components reused; no one-off styling or duplication
+5. **Responsive Behavior** — layouts adapt across viewports
+6. **Fit with Design Language** — border radius, shadows, transitions, icon style match patterns
+
+## Output Format
+
+End your response with a JSON verdict block:
+
+For clean reviews:
+\`\`\`json-workflow-verdict
+{"verdict":"PASS","notes":"<1-2 sentence summary>"}
+\`\`\`
+
+For issues requiring code changes:
+\`\`\`json-workflow-verdict
+{"verdict":"FAIL","notes":"<specific files and what needs to change>"}
+\`\`\`
+
+Prioritize: layout breaks > visual inconsistency > style preferences.
+Do NOT spend time on nits when no real issues exist.`;
+
+const STEP_ID = "frontend-ux-design";
+
+async function main() {
+  if (dryRun) {
+    console.log("=== DRY RUN: New WS-006 prompt ===\n");
+    console.log(NEW_PROMPT);
+    console.log("\n=== End of prompt ===");
+    return;
+  }
+
+  const resolvedPath = resolve(dbPath);
+  console.log(`Opening database: ${resolvedPath}`);
+
+  const db = new Database(resolvedPath);
+
+  // Check if the workflow step exists
+  const row = db.prepare("SELECT id, name, prompt FROM workflow_steps WHERE id = ?").get(STEP_ID);
+
+  if (!row) {
+    console.error(`Workflow step '${STEP_ID}' not found in database. No action taken.`);
+    db.close();
+    process.exit(0);
+  }
+
+  console.log(`Found workflow step: ${row.name} (${row.id})`);
+  console.log(`Old prompt length: ${row.prompt?.length ?? 0} chars`);
+  console.log(`New prompt length: ${NEW_PROMPT.length} chars`);
+
+  const result = db.prepare("UPDATE workflow_steps SET prompt = ?, updatedAt = ? WHERE id = ?").run(
+    NEW_PROMPT,
+    new Date().toISOString(),
+    STEP_ID,
+  );
+
+  console.log(`Updated ${result.changes} row(s).`);
+  db.close();
+}
+
+main().catch((err) => {
+  console.error("Error:", err.message);
+  process.exit(1);
+});