feat(clients): register Trae during setup (#1573)

* feat(clients): register Trae during setup

- SupportedClients: trae definition (VS Code-style user directory,
  User/mcp.json, format json)
- Trae documents mcpServers as the top-level server table with
  command/args/env and stdio as the default transport; it has no
  personal skills directory, so setup skips the skill copy
- tests: traeClientConfiguration.test.ts (per-platform user directory
  resolution, upsert preserving unrelated settings, fresh/empty
  configs, uninstall)

Verified: tsc --noEmit clean; vitest run
tests/boundary/filesystem/traeClientConfiguration.test.ts 6/6.

* fix(clients): install Trae's personal REA skill

Review follow-up (#1573): the Trae Skills documentation lists global
skills under ~/.trae/skills on macOS/Linux and %userprofile%/.trae/skills
on Windows, so the definition now carries that skillPath and setup
installs the bundled skill copy there. The installation docs no longer
claim Trae has no personal skills directory, and the bundled REA
skill's supported client list includes trae.

Verified: tsc --noEmit clean; vitest run
tests/boundary/filesystem/traeClientConfiguration.test.ts 7/7.

* docs(clients): qualify Trae configuration path evidence

---------

Co-authored-by: morluto <76467478+morluto@users.noreply.github.com>

docs/client-configuration.md

@@ -145,6 +145,21 @@ REA follows `HERMES_HOME` whitespace trimming, environment-variable expansion,
 and home expansion before resolving that profile. Setup previews the resolved
 configuration and skill destinations; doctor and uninstall use those same paths.
 
+## Trae
+
+For [Trae](https://docs.trae.ai/ide/add-mcp-servers), setup writes
+`mcpServers.rea` into the user-scope `mcp.json` under Trae's VS Code-style
+user directory (`%APPDATA%\Trae\User` on Windows,
+`~/Library/Application Support/Trae/User` on macOS, and
+`~/.config/Trae/User` elsewhere). Entries carry `command`, `args`, and
+`env`; stdio is the default transport. Trae discovers personal skills from
+`~/.trae/skills` (`%userprofile%\.trae\skills` on Windows), so setup
+installs its skill copy there.
+
+The user-level MCP paths follow the editor's VS Code layout. Trae's official
+documentation describes the raw JSON editor without specifying those paths;
+loading this registration in Trae remains unverified.
+
 ## ZCode
 
 For [ZCode](https://zcode.z.ai/en/docs/mcp-services), setup registers `rea` in the nested `mcp.servers` table of the