v0.4.0: fix MCP tool names (vim_* not nvim_*)

mcp-neovim-server exposes tools named vim_command, vim_buffer,
vim_status, vim_edit, vim_window, vim_file_open, vim_search, etc. —
all with a vim_ prefix and with no eval tool. The agent and skills
previously referenced mcp__neovim__nvim_command and
mcp__neovim__nvim_eval, which do not exist, so every drive/introspect
call would have failed to resolve.

- agents/companion.md: add the full vim_* tool reference table; note
  that lua is evaluated via vim_command with :lua print(...)
- skills/editor-introspect: add a 'tools you have' section; correct
  the runnable-via line
- skills/editor-act: correct the description's tool references

skills/claude-code-handoff/SKILL.md

@@ -60,7 +60,7 @@ These are defined under `<leader>a*` in
 
 ## The full `:ClaudeCode*` command surface
 
-When driving the editor via `mcp__neovim__nvim_command` you have more
+When driving the editor via `mcp__neovim__vim_command` you have more
 than the keymaps above. The complete set:
 
 - `:ClaudeCode` — toggle the terminal split.
@@ -88,7 +88,7 @@ quoting them.
 
 1. **Confirm the split is open.** Either ask `editor-introspect` to
    check for a Claude Code buffer/window, or just run
-   `:ClaudeCode` via `mcp__neovim__nvim_command` — the command is
+   `:ClaudeCode` via `mcp__neovim__vim_command` — the command is
    idempotent (toggles, but if already visible the user sees no
    surprise).
 
@@ -104,7 +104,7 @@ quoting them.
    neovim.nix add a keymap for ...", say "add a `<leader>tw` keymap
    that toggles wrap, next to the existing wrap-toggle block."
    Send via `:ClaudeCodeSend` (after selection) or by typing the
-   prompt into the Claude Code buffer (`mcp__neovim__nvim_command`
+   prompt into the Claude Code buffer (`mcp__neovim__vim_command`
    plus an explicit feedkeys is overkill — usually the user can type
    it themselves once focus is in the split).
 

skills/editor-act/SKILL.md

@@ -3,11 +3,12 @@ name: editor-act
 description: |
   Drive the user's running Neovim instance — open files, run user
   commands, trigger keymaps, jump to LSP locations, toggle UI,
-  evaluate small lua snippets. Uses `mcp__neovim__nvim_command` /
-  `nvim_eval` against the live instance. Prefers the user's own
-  commands and keymaps over teaching new vim syntax. Will *not* edit
-  buffer contents — that work is handed off via the
-  `claude-code-handoff` skill. Trigger on "open <file> in nvim",
+  evaluate small lua snippets. Uses the `mcp__neovim__*` tools
+  (`vim_command`, `vim_file_open`, `vim_window`, …) against the live
+  instance. Prefers the user's own commands and keymaps over teaching
+  new vim syntax. Will *not* edit buffer contents — that work is
+  handed off via the `claude-code-handoff` skill. Trigger on
+  "open <file> in nvim",
   "jump to definition of", "show file finder", "split this", "toggle
   neo-tree", "run this command in my nvim", "go to next diagnostic",
   "save my buffer".

skills/editor-introspect/SKILL.md

@@ -33,11 +33,27 @@ present in this session, **stop and tell the user**:
 
 Do not try to fake introspection from the config alone.
 
+## The tools you have
+
+`mcp-neovim-server` exposes these (note the `vim_` prefix, *not*
+`nvim_`):
+
+- `mcp__neovim__vim_command` — run any `:` command, including `:lua`.
+  Returns the rendered command output. This is the workhorse for
+  introspection: pass `:verbose nmap ...`, `:lua print(...)`, etc.
+- `mcp__neovim__vim_status` — cursor, mode, marks, registers in one
+  call. Use instead of three separate `:lua` calls.
+- `mcp__neovim__vim_buffer` — buffer contents with line numbers.
+- `mcp__neovim__vim_health` — check the nvim↔server connection; run
+  this first if anything seems disconnected.
+
+There is **no eval tool**. To get a lua value, call `vim_command`
+with `:lua print(vim.inspect(<expr>))` and parse the printed output.
+
 ## The introspection vocabulary
 
-These are the queries you should reach for first. All are runnable
-via `mcp__neovim__nvim_command` (returns the rendered command output)
-or `mcp__neovim__nvim_eval` (returns a value).
+Queries to reach for first. Unless noted, run each as the `command`
+argument to `mcp__neovim__vim_command`.
 
 ### Keymaps