fix: remaining personal identifiers in wezterm, sway, email.service (PR #81 not merged)

[stanfish06]

PR #81 addressed these three leaks but was closed without merging. They are still present in master as of the May 22 "gentoo" commit.

1. wezterm/.wezterm.lua — Windows username zhiyu in background path (info leak)

-- current
{ source = { File = "C:/Users/zhiyu/Desktop/Git/my-configs/img/dark-green-forest.jpg" }, opacity = 0.4 },

-- fix: use wezterm.home_dir for portability
{ source = { File = wezterm.home_dir .. "/.config/wezterm/background.jpg" }, opacity = 0.4 },

Wire up once at deploy time:

New-Item -ItemType SymbolicLink -Path "$env:USERPROFILE\.config\wezterm\background.jpg" -Target "$env:USERPROFILE\Desktop\Git\my-configs\img\dark-green-forest.jpg"

2. sway/40-sway-background.conf — /home/stanfish/ hardcoded (info leak + compatibility break)

# current
output * bg /home/stanfish/Git/my-configs/img/space.jpeg fill

# fix
output * bg ~/.config/sway/wallpaper.jpeg fill

Wire up once at deploy time:

ln -sf ~/Git/my-configs/img/space.jpeg ~/.config/sway/wallpaper.jpeg

3. linux/services/email.service — User=stanfish and /home/stanfish/ (info leak + compatibility break)

# current
User=stanfish
ExecStart=/home/stanfish/scripts/system/fetch-emails.sh

# fix: use %h systemd specifier; set User= locally per machine
# User=  # set locally: User=your-username
ExecStart=%h/scripts/system/fetch-emails.sh