feat(migration): implement workspace layout migration and testing

- Added `migrate-layout.ts` to handle migration from old workspace layouts to the new `devclaw/` structure.
- Introduced `migrate-layout.test.ts` for comprehensive tests covering various migration scenarios.
- Updated `workspace.ts` to ensure default files are created post-migration, including `workflow.yaml` and role-specific prompts.
- Refactored role instruction handling to accommodate new directory structure.
- Enhanced project registration to scaffold prompt files in the new `devclaw/projects/<project>/prompts/` directory.
- Adjusted setup tool descriptions and logic to reflect changes in file structure.
- Updated templates to align with the new workflow configuration and role instructions.

lib/tools/design-task.ts

@@ -14,6 +14,7 @@ import { dispatchTask } from "../dispatch.js";
 import { log as auditLog } from "../audit.js";
 import { requireWorkspaceDir, resolveProject, resolveProvider, getPluginConfig } from "../tool-helpers.js";
 import { loadWorkflow, getActiveLabel, getQueueLabels } from "../workflow.js";
+import { loadConfig } from "../config/index.js";
 import { selectLevel } from "../model-selector.js";
 import { resolveModel } from "../roles/index.js";
 
@@ -123,7 +124,9 @@ Example:
       const level = complexity === "complex"
         ? selectLevel(title, "system-wide " + description, role).level
         : selectLevel(title, description, role).level;
-      const model = resolveModel(role, level, pluginConfig);
+      const resolvedConfig = await loadConfig(workspaceDir, project.name);
+      const resolvedRole = resolvedConfig.roles[role];
+      const model = resolveModel(role, level, resolvedRole);
 
       if (dryRun) {
         return jsonResult({