Switch agent job image to Fedora with QoL CLI tooling + neutral shell defaults

- Base fedora:41; reinstall toolchain (node 22, gcc/c++, neovim, tmux, git, etc.)
- Add QoL CLI from the user's Panama setup, all in default Fedora repos: zoxide,
  eza, bat, fzf, fd, gh, gum, ripgrep, bash-completion; oh-my-posh via installer;
  pnpm/yarn/bun via npm; keep codex@0.142.0 + opencode@1.17.9 pinned
- Ship neutral system-wide defaults that work even with an empty/mounted HOME:
  /etc/profile.d/spoon.sh (zoxide/eza/fzf/oh-my-posh init + aliases),
  /etc/tmux.conf (login-shell panes), /etc/spoon/omp.json (default prompt theme)
- .dockerignore: re-include docker/agent-job-rootfs into the build context
- Verified: codex runs a real turn on Fedora (exit 0); all tools present

docker/agent-job-rootfs/etc/tmux.conf

@@ -0,0 +1,12 @@
+# Spoon container — system tmux defaults. A user's ~/.config/tmux/tmux.conf (or
+# ~/.tmux.conf) is read after this and overrides it.
+
+# Login shells so /etc/profile.d/spoon.sh (tools) and ~/.bash_profile load.
+set -g default-command "exec bash -l"
+set -g default-terminal "tmux-256color"
+set -ag terminal-overrides ",xterm-256color:RGB"
+set -g mouse on
+set -g history-limit 50000
+set -g escape-time 10
+set -g focus-events on
+setw -g mode-keys vi