chore: sweep dead config — thefuck, aider, tmux/oh-my-posh leftovers, nvim starter cruft, dead ignore patterns

- thefuck: remove the empty home_config/thefuck dir left behind after 2026-06-26's
  'drop thefuck'. Its ~/.config link, the ~/homebase venv that held only thefuck and
  its deps, and the thefuck/fuck wrappers were removed from nh3-dev at the same time.
- aider: remove .aider.conf.yml and .aider.model.settings.yml. The only configured
  backend was an Ollama qwq-32b endpoint, and the last session was 2025-03-21.
  Repo-root aider session artifacts were deleted and the aider-chat uv tool was
  uninstalled on nh3-dev.
- stow ignores: delete .stow-global-ignore and home_config/.stow-local-ignore. Their
  patterns were tmux plugins (the tmux config is gone) and ~/-prefixed paths that
  stow never matches, so they only displaced stow's built-in defaults.
- nvim: drop kickstart's vimtutor TEST file and upstream .github templates/CI.
- .gitignore: drop dead patterns (.config/*, /.aider*). Ignore per-machine zellij
  layouts, and guard Claude Code credentials and settings.local.json.

Dangling ~/.tmux.conf, ~/.config/tmux and ~/.config/ohmyposh links were also removed on nh3-dev.

home_root/.aider.conf.yml

@@ -1,8 +0,0 @@
-# Aider config — active settings only (full option reference: aider.chat/docs/config.html)
-model: ollama_chat/qwq-32b-iq6kl
-
-set-env:
-  - OLLAMA_API_BASE=http://10.250.50.51:11434
-
-alias:
-  - "o-qwq:ollama_chat/qwq-32b-iq6kl"

home_root/.aider.model.settings.yml

@@ -1,9 +0,0 @@
-- name: ollama_chat/qwq-32b-iq6kl
-  edit_format: diff
-  reasoning_tag: think
-  use_temperature: 0.6
-  extra_params:
-    top_p: 0.95
-    top_k: 40
-    repetition_penalty: 1.0
-

home_root/.stow-global-ignore

@@ -1,5 +0,0 @@
-~/.config/tmux/plugins
-~/.config/btop
-~/.config/neofetch
-~/.config/zinit
-