mrun 0.1.0

First release. Extracted from mshell, whose
built-in launcher this replaces.

Added

• A launcher that is its own program. mshell's built-in one indexed the
  Start menu and did nothing else: no config, no way to add a source, no way to
  add a mode. Extending it in place would have meant growing the window manager
  every time the launcher learned something new.

  Being a separate process also fixes the hardest part. An overlay painted by a
  window manager is typically WS_EX_NOACTIVATE and cannot take the foreground,
  so it can only be typed into by intercepting the keyboard globally and
  forwarding keystrokes to itself — a capture mode whose failure case is a dead
  keyboard. mrun is an ordinary process with an ordinary focused window and
  reads keys the way every other application does.

• A module system. Every result comes from a module, behind one interface
  (init / configure / search / activate). apps is the first, indexing
  both Start menus; clipboard history and emoji are the obvious next ones and
  register the same way.

  A module is also writable entirely in Lua, against the same interface:

  mrun.set_modules({ "apps", "calc" })     -- enabled, in search order
  
  mrun.module({
      name     = "calc",
      prefix   = "=",                       -- typing "=" searches only this
      search   = function(query) ... end,   -- runs on every keystroke
      activate = function(item) ... end,    -- runs on Enter
  })

  Module names are resolved after the whole config has run, so the order things
  are declared in the file does not matter.

• Fuzzy matching — subsequence, with prefix, word-boundary and camelCase
  hits ranked above scattered ones, consecutive runs rewarded and long gaps
  penalised. vsc finds Visual Studio Code. A row may supply its own score
  to override the ranking. Unit-tested (make test), being the one part with no
  Windows in it.

• A resident instance with a client CLI. The first invocation goes resident;
  every later one is a client that tells it what to do and exits (--toggle,
  --show, --hide, --query, --mode, --reload, --quit). Binding
  mrun.exe to a hotkey therefore gives a toggle rather than a second copy, and
  --daemon at login makes the first open instant.

• Lua configuration, at %APPDATA%\mrun\init.lua or config\mrun.lua
  beside the exe. mrun.set_appearance{} covers size, colours, fonts, opacity,
  rounding and position; mrun.set_behaviour{} covers hide-on-blur and whether
  the query survives a close. --check validates a config from the command
  line.

  A config error is atomic: the whole file is rejected and mrun runs on
  built-in defaults rather than half of what you wrote.

• Per-monitor DPI awareness, declared in the manifest so it applies before
  the first window exists and costs no load-time dependency on a user32 export
  that older Windows lacks.

Notes

• The portable config file is config\mrun.lua rather than config\init.lua
  deliberately: mrun.exe is often dropped beside mshell.exe, whose own config
  is config\init.lua, and two programs reading the same filename out of the
  same folder is a trap.
• The log goes to %LOCALAPPDATA%\mshell\mrun.log, which log.c inherited from
  mshell along with the file itself.