chore: Mount user Copilot instructions into devcontainer (#5607)

- Mount ~/.github/instructions from host to devcontainer
- Symlink mounted instructions to workspace .github/instructions
- Add .github/instructions to gitignore

.devcontainer/docker-compose.yml

@@ -13,6 +13,7 @@ services:
       # preserve history
       - ./.local:/home/node/.local
       - docker-data:/var/lib/docker
+      - ${HOME}/.github/instructions:/home/node/.github/instructions
 
     entrypoint: ["/usr/local/share/docker-init.sh"]
     # Overrides default command so things don't shut down after the process ends.

.devcontainer/postinstall.sh

@@ -42,5 +42,11 @@ alias gitclean="(git remote | xargs git remote prune) && git branch -vv | egrep
 alias gitrebase="git rebase --interactive main"
 EOF
 
+# Symlink workspace GitHub instructions to mounted user instructions (for Copilot)
+if [ -d "/home/node/.github/instructions" ]; then
+  mkdir -p /workspaces/webstudio/.github
+  ln -sfn /home/node/.github/instructions /workspaces/webstudio/.github/instructions
+fi
+
 
 echo "postinstall.sh finished"

.gitignore

@@ -64,3 +64,6 @@ packages/prisma-client/src/__generated__
 
 .temp
 *.timestamp-*.mjs
+
+# copilot instructions
+.github/instructions