fix: Correct workflow-session.json path references in brainstorming docs

- Fix incorrect path: .brainstorming/workflow-session.json → /workflow-session.json
- Update 8 role files: data-architect, product-manager, product-owner, scrum-master,
  subject-matter-expert, ui-designer, ux-expert, auto-parallel
- Update artifacts.md to clarify correct session file location
- Align all paths with workflow-architecture.md standard structure

Fixes session file path confusion issue. workflow-session.json should be at
session root (.workflow/WFS-{session}/), not in .brainstorming/ subdirectory.

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

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

.claude/commands/workflow/brainstorm/auto-parallel.md

@@ -149,7 +149,7 @@ Task(subagent_type="conceptual-planning-agent",
 
      3. **load_session_metadata**
         - Action: Load session metadata and topic description
-        - Command: bash(cat .workflow/WFS-{topic}/.brainstorming/workflow-session.json 2>/dev/null || echo '{}')
+        - Command: bash(cat .workflow/WFS-{topic}/workflow-session.json 2>/dev/null || echo '{}')
         - Output: session_metadata
 
      ### Implementation Context
@@ -162,7 +162,7 @@ Task(subagent_type="conceptual-planning-agent",
      ### Session Context
      **Workflow Directory**: .workflow/WFS-{topic}/.brainstorming/
      **Output Directory**: .workflow/WFS-{topic}/.brainstorming/{role}/
-     **Session JSON**: .workflow/WFS-{topic}/.brainstorming/workflow-session.json
+     **Session JSON**: .workflow/WFS-{topic}/workflow-session.json
 
      ### Dependencies & Context
      **Topic**: {user-provided-topic}