refactor: rebrand npm packages @uncaged/* → @united-workforce/*

Package mapping:
- @uncaged/cli-workflow → @united-workforce/cli
- @uncaged/workflow-protocol → @united-workforce/protocol
- @uncaged/workflow-util → @united-workforce/util
- @uncaged/workflow-util-agent → @united-workforce/util-agent
- @uncaged/workflow-agent-hermes → @united-workforce/agent-hermes
- @uncaged/workflow-agent-claude-code → @united-workforce/agent-claude-code
- @uncaged/workflow-agent-builtin → @united-workforce/agent-builtin
- @uncaged/workflow-dashboard → @united-workforce/dashboard

Changes:
- 8 package.json name + dependency refs
- 82 files: import statements updated
- .changeset/config.json updated
- CLAUDE.md updated
- bunfig.toml restored for preload

CLI command (uwf) and directory names unchanged.

Closes shazhou/united-workforce#8

packages/workflow-agent-builtin/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "@uncaged/workflow-agent-builtin",
+  "name": "@united-workforce/agent-builtin",
   "version": "0.5.0",
   "files": [
     "src",
@@ -24,8 +24,8 @@
   },
   "dependencies": {
     "@ocas/core": "^0.1.1",
-    "@uncaged/workflow-util-agent": "workspace:^",
-    "@uncaged/workflow-util": "workspace:^"
+    "@united-workforce/util-agent": "workspace:^",
+    "@united-workforce/util": "workspace:^"
   },
   "devDependencies": {
     "typescript": "^5.8.3"