security(home): drop all neovim plugins to shrink supply-chain exposure (#259)

* chore(home): drop AstroNvim bundle and centralize editors

Remove the bundled Neovim plugin tree to shrink supply-chain exposure; keep a
minimal programs.neovim backup. Daily editing stays Helix-first with Yazi and
Zellij.

- Add Helix/Neovim docs, glossary, and cheatsheets under core/editors/.
- Default EDITOR/VISUAL to hx; use SUDO_EDITOR nvim --clean for sudoedit and
  other sensitive edits; adjust Nushell buffer_editor accordingly.
- Apply Helix Home Manager settings (keys, editor UI) in core/editors/helix.
- Keep heavy language-server tooling only in home/base/tui/editors/packages.nix;
  wire it via an explicit default.nix import so core stays lightweight.
- Extend modules/base packages.nix where that profile sets global editor env.

* docs: link editors, VS Code, and agents from README

Document tui/editors versus core/editors; add root README pointers to GUI
vscode (Home Manager) and agents/. Cross-link heavy packages README from
core/editors.

home/base/tui/editors/neovim/nvim/lua/community.lua

@@ -1,55 +0,0 @@
--- AstroCommunity: import any community modules here
--- We import this file in `lazy_setup.lua` before the `plugins/` folder.
--- This guarantees that the specs are processed before any user plugins.
-
----@type LazySpec
-return {
-  "AstroNvim/astrocommunity",
-  -- Motion
-  { import = "astrocommunity.motion.mini-surround" },
-  -- https://github.com/echasnovski/mini.ai
-  { import = "astrocommunity.motion.mini-ai" },
-  { import = "astrocommunity.motion.flash-nvim" },
-  -- Highly experimental plugin that completely replaces
-  -- the UI for messages, cmdline and the popupmenu.
-  -- { import = "astrocommunity.utility.noice-nvim" },
-  { import = "astrocommunity.media.vim-wakatime" },
-  { import = "astrocommunity.motion.leap-nvim" },
-  { import = "astrocommunity.motion.flit-nvim" },
-  { import = "astrocommunity.scrolling.nvim-scrollbar" },
-  { import = "astrocommunity.editing-support.todo-comments-nvim" },
-  -- Language Support
-  ---- Frontend & NodeJS
-  { import = "astrocommunity.pack.typescript-all-in-one" },
-  { import = "astrocommunity.pack.tailwindcss" },
-  { import = "astrocommunity.pack.html-css" },
-  { import = "astrocommunity.pack.prisma" },
-  { import = "astrocommunity.pack.vue" },
-  ---- Configuration Language
-  { import = "astrocommunity.pack.markdown" },
-  { import = "astrocommunity.pack.json" },
-  { import = "astrocommunity.pack.yaml" },
-  { import = "astrocommunity.pack.toml" },
-  ---- Backend / System
-  { import = "astrocommunity.pack.lua" },
-  { import = "astrocommunity.pack.go" },
-  { import = "astrocommunity.pack.rust" },
-  { import = "astrocommunity.pack.python" },
-  { import = "astrocommunity.pack.java" },
-  { import = "astrocommunity.pack.cmake" },
-  { import = "astrocommunity.pack.cpp" },
-  -- { import = "astrocommunity.pack.nix" },  -- manually add config for nix, comment this one.
-  { import = "astrocommunity.pack.proto" },
-
-  ---- Operation & Cloud Native
-  { import = "astrocommunity.pack.terraform" },
-  { import = "astrocommunity.pack.bash" },
-  { import = "astrocommunity.pack.docker" },
-  { import = "astrocommunity.pack.helm" },
-
-  -- colorscheme
-  { import = "astrocommunity.colorscheme.catppuccin" },
-
-  -- Lua implementation of CamelCaseMotion, with extra consideration of punctuation.
-  { import = "astrocommunity.motion.nvim-spider" },
-}