default backslash (\) leader key not detected even when explicitly set in config

[ddl004]

Dotfyle reports leaderkey: unknown for my config even though I explicitly set a backslash leader at the top of my init.lua.

vim.g.mapleader = "\\"

It looks like the findLeaderKey() function in src/lib/server/nvim-sync/config/NeovimConfigSyncer.ts has a small escaping bug in the switch statement.

Proposed fix:

- case '"\\"':
- case "'\\'":
+ case '"\\\\"':
+ case "'\\\\'":
    return '\\';

These string literals only contain a single backslash, but the raw text from a Lua file with vim.g.mapleader = "\\" should be escaped as \\\\.