feat: add bootstrap module and update docs

- Add lua/bootstrap.lua: redirects Neovim data/state paths when running
  as root (e.g. via symlinked ~/.config/nvim) to prevent root sessions
  from conflicting with the user-level install
- Update init.lua to require("bootstrap") before any other module
- Standardize license headers across all Lua files (capitalize author,
  add SPDX-License-Identifier)
- Update README with full plugin stack section, bootstrap docs,
  machine-local override docs, qalculate dependency, and blink.cmp
  auto-rebuild note

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lua/const.lua

@@ -4,6 +4,9 @@
   └────────────────────────────────────────────────────────────────┘
 --]]
 
+-- Copyright (C) 2026 Rootiest
+-- SPDX-License-Identifier: GPL-3.0-or-later
+
 local M = {}
 
 --- Dashboard Header