Change Zellij pane background color based on project path (flakes-dkc4)

Visually distinguish panes belonging to different projects by assigning each project a unique background color in Zellij. Builds on the project-wise pane naming from flakes-1zlj.

Design

Palette

8 subtle Gruvbox-adjacent background tints (base bg is #282828):

Color Assignment

• Hash project name (simple checksum) mod palette size → deterministic color index
• Same project always gets the same color
• Known limitation: hash collisions possible, acceptable for now

Behavior

• Home project (ZELLIJ_SESSION_PROJECT): no color change, stays at terminal default
• Foreign project: apply palette color via zellij action set-pane-color --bg
• On return to home project: zellij action set-pane-color --reset
• Applied on PWD change and shell init

Files Changed

modules/home/programs/fish/init/zellij.fish only.

Tasks

• Add color palette array
• Add hash function for project name → palette index
• Add zellij_update_pane_color function
• Integrate into PWD hook and init block
• Reset color when returning to home project

Summary of Changes

Added to modules/home/programs/fish/init/zellij.fish:

• ZELLIJ_PANE_COLORS: 8 subtle Gruvbox-adjacent bg tints
• zellij_project_color_index: djb2-style hash mod palette size, returns stable integer index
• zellij_update_pane_color: applies color for foreign projects, resets for home project
• Called from PWD hook and init block alongside existing pane/tab name updates