## Summary

Opening the keybindings menu (`omarchy-menu-keybindings`) can spawn a `lua` subprocess that spins at 100% CPU **forever**, hanging the menu and pegging a core (observed 10+ minutes, package temp up to 96°C). The spinner is `build_lua_bind_cache`'s mock-environment scan of the user's `~/.config/hypr/hyprland.lua`.

## Root cause

`build_lua_bind_cache` executes the user's real `hyprland.lua` against a mock `hl` table whose `__index` falls back to a `noop` sentinel table:

```lua
local noop
noop = setmetatable({}, {
  __index = function() return noop end,
  __call  = function() return noop end,
})
```

`noop`'s `__index` returns `noop` for **any** key — including numeric keys. So any user config that iterates over a real Hyprland Lua API that the mock doesn't implement (e.g. `hl.get_loaded_plugins()` used by the CUA plugin setup) gets `noop` back, and:

```lua
for _, plugin in ipairs(hl.get_loaded_plugins()) do ... end
```

never terminates: `ipairs` stops when `t[n]` is `nil`, but `noop[1]`, `noop[2]`, … all resolve to `noop` via `__index`. Pure CPU spin, no syscalls (confirmed with `strace`).

## Minimal repro

```bash
sed -n '79,232p' /usr/share/omarchy/bin/omarchy-menu-keybindings > /tmp/scan.lua
# add `for _ in ipairs(hl.get_loaded_plugins()) do end` to ~/.config/hypr/hyprland.lua
timeout 5 lua /tmp/scan.lua   # exit=124, hangs
```

Confirmed on stock 4.0.4: the scan prints all registered binds (236 lines) then spins in the user-config loop. Reverting the `ipairs` loop to a `#`-bounded numeric loop makes the scan exit normally.

## Suggested fix

Two options, either works:

1. `noop.__index` returns `nil` for numeric keys (preserves method-chaining, lets `ipairs`/`next` terminate):
   ```lua
   __index = function(_, key)
     return type(key) == "number" and nil or noop
   end
   ```
2. Explicitly stub real `hl` APIs in the mock (`hl.get_loaded_plugins = function() return {} end`).

## Secondary observation

The mock defines `hl` but not `o` (window-rule API). User configs calling `o.window(...)` fail under the scan — silently swallowed by `pcall`, so window rules just don't appear in the menu. Not a hang, but same class of gap.

## Environment

- Omarchy 4.0.4-1 (package `omarchy-menu-keybindings`)
- Hyprland 0.56.2
- Lua 5.5.1