Sakura Line: retheme the whole desktop from the wallpaper

Palette sampled from bspwm/wallpaper/wallpaper.jpg and applied per-role
(not per-hex, so terminal green stays green and nvim's LineNr/Comment
stay recessive) across st, kitty, polybar, rofi, dunst, nvim, qt5ct/qt6ct
and GTK 2/3/4.

Also:
- rofi drun centred, icons enabled
- polybar translucent (true ARGB) and rounded; picom corner-radius, with
  the desktop layer and fullscreen windows excluded
- fix qt5ct color_scheme_path pointing at a nonexistent /home/carrie
- export QT_QPA_PLATFORMTHEME so qt6ct is actually consulted
- point GTK at an icon theme that exists on this system
- add .config/rice: one-shot install.sh (--dry-run supported), package
  list, vendored st config.h (gitignored upstream) and the particles
  wallpaper-layer source, so a clone reproduces the rice

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Cn3dHfbgNYdbZvzb1b3GQt

.config/rice/README.md

@@ -0,0 +1,61 @@
+# Sakura Line
+
+bspwm rice. Palette sampled from `~/.config/bspwm/wallpaper/wallpaper.jpg`.
+
+## Replicate on a fresh machine
+
+```sh
+bash <(curl -fsSL https://git.srtk.in/sarthak/dotfiles/raw/branch/main/.config/rice/install.sh)
+```
+
+Or, if the dotfiles are already cloned:
+
+```sh
+~/.config/rice/install.sh            # full run
+~/.config/rice/install.sh --dry-run  # show what it would do, change nothing
+```
+
+Arch is the first-class target. Debian/Ubuntu and Fedora are best-effort —
+the desktop, build and theming steps work; the AUR extras are skipped.
+
+The script is safe to re-run. Anything in `$HOME` that would be overwritten by
+the dotfiles checkout is moved to `~/.rice-backup-<timestamp>/` first.
+
+## What it sets up
+
+| | |
+|---|---|
+| WM | bspwm + sxhkd |
+| Bar | polybar (translucent, rounded) |
+| Compositor | picom (rounded corners, vsync) |
+| Launcher | rofi, centred, with icons |
+| Notifications | dunst |
+| Terminal | st, built from `st/config.h` here (upstream gitignores it) |
+| Wallpaper layer | `particles`, built from `particles/` here |
+| Toolkits | GTK2/3/4 via `gtk.css` overrides, Qt via qt6ct |
+
+## Palette
+
+| role | hex | from |
+|---|---|---|
+| bg | `#0f0d17` | twilight shadow |
+| fg | `#e9eefb` | cool white |
+| accent | `#92b9ea` | sky |
+| red | `#cf6a80` | blossom |
+| green | `#8fae74` | grass |
+| yellow | `#d8a87c` | train stripe |
+| magenta | `#b483c0` | plum blossom |
+| cyan | `#8ab6c4` | station house |
+
+Changing the wallpaper does not re-derive these — they are written into each
+app's config.
+
+## Layout
+
+```
+.config/rice/
+├── install.sh        one-shot bootstrap
+├── packages.txt      package list ("aur:" prefix = needs an AUR helper)
+├── st/config.h       st build config
+└── particles/        wallpaper-layer particle field (source + Makefile)
+```