feat(lsp): add PowerShellEditorServices language server (#55930)

Registers PowerShell (.ps1/.psm1/.psd1) in the LSP server registry,
spawning PowerShellEditorServices over stdio via a pwsh/powershell
host. PSES ships as a GitHub release zip (no npm/go/pip recipe), so it
sits in the manual install tier alongside rust-analyzer and clangd.

The spawn builder resolves the module bundle from (in order) the
lsp.servers.powershell.command override, init bundlePath, the
PSES_BUNDLE_PATH env var, or <HERMES_HOME>/lsp/PowerShellEditorServices,
then launches Start-EditorServices.ps1 -Stdio with a non-interactive,
no-profile host. hermes lsp status/list report it as manual-only until
pwsh is present.

Docs and tests included.

website/docs/user-guide/features/lsp.md

@@ -86,12 +86,35 @@ agent sees a syntax-clean file with semantic problems as
 | Prisma | `prisma language-server` | manual |
 | Kotlin | `kotlin-language-server` | manual |
 | Java | `jdtls` | manual |
+| PowerShell | `PowerShellEditorServices` (`pwsh` host) | manual (release zip) |
 
 For "manual" entries, install the server through whatever toolchain
 manager makes sense for that language (rustup, ghcup, opam, brew,
 …). Hermes auto-detects the binary on PATH or in
 `<HERMES_HOME>/lsp/bin/`.
 
+### PowerShell
+
+PowerShellEditorServices isn't a single binary — it's a PowerShell
+module bundle launched by a `pwsh` (PowerShell 7+) or `powershell`
+host. Setup:
+
+1. Install [PowerShell](https://github.com/PowerShell/PowerShell) so
+   `pwsh` (or Windows `powershell`) is on PATH.
+2. Download the latest release zip from
+   [PowerShellEditorServices releases](https://github.com/PowerShell/PowerShellEditorServices/releases)
+   and extract it.
+3. Point Hermes at the extracted bundle — the directory that contains
+   `PowerShellEditorServices/Start-EditorServices.ps1`. Either:
+   - set `lsp.servers.powershell.command: ["/path/to/bundle"]` in
+     `config.yaml`, or
+   - extract it to `<HERMES_HOME>/lsp/PowerShellEditorServices`, or
+   - export `PSES_BUNDLE_PATH=/path/to/bundle`.
+
+`hermes lsp status` reports `installed` once `pwsh` is found; if the
+bundle is missing you'll see a one-time warning in the logs with the
+download link.
+
 A few servers are installed alongside a peer dependency that npm
 won't auto-pull. The current case is `typescript-language-server`,
 which requires the `typescript` SDK importable from the same