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/README.md

@@ -1,4 +1,4 @@
-# @uncaged/workflow-agent-builtin
+# @united-workforce/agent-builtin
 
 `uwf-builtin` agent — built-in LLM agent with file read/write and shell tools.
 
@@ -8,14 +8,14 @@ Layer 3 agent implementation. Runs an OpenAI-compatible chat completion loop wit
 
 Useful when you want a self-contained agent without an external CLI like Hermes or Claude Code.
 
-**Dependencies:** `@ocas/core`, `@uncaged/workflow-util-agent`, `@uncaged/workflow-util`
+**Dependencies:** `@ocas/core`, `@united-workforce/util-agent`, `@united-workforce/util`
 
 ## Installation
 
-Included as the `uwf-builtin` binary when you install `@uncaged/workflow-agent-builtin`:
+Included as the `uwf-builtin` binary when you install `@united-workforce/agent-builtin`:
 
 ```bash
-bun add -g @uncaged/workflow-agent-builtin
+bun add -g @united-workforce/agent-builtin
 ```
 
 ## CLI Usage