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

.changeset/config.json

@@ -2,10 +2,10 @@
   "$schema": "https://unpkg.com/@changesets/config@3.1.4/schema.json",
   "changelog": "@changesets/cli/changelog",
   "commit": false,
-  "fixed": [["@uncaged/*"]],
+  "fixed": [["@united-workforce/*"]],
   "linked": [],
   "access": "public",
   "baseBranch": "main",
   "updateInternalDependencies": "patch",
-  "ignore": ["@uncaged/workflow-dashboard"]
+  "ignore": ["@united-workforce/dashboard"]
 }