copy laravel app root instead of symlinking

PHP's __DIR__ follows symlinks, so an artisan symlink at
/var/lib/tide/app/artisan resolved back to the read only store
path. That made every Laravel file path ultimately resolve into
the store, including storage/logs/laravel.log and bootstrap/cache,
which Laravel must be able to write. The redirected symlinks for
those two subtrees never even got consulted because resolution
happened upstream of them.

Switch tide-prepare to copy the package contents into appRoot,
then mount /var/lib/tide/state over storage/ and bootstrap/cache/
via symlinks out of a writable parent. Now __DIR__ resolves to
the writable copy and Laravel can boot.

nix/module.nix

@@ -139,29 +139,24 @@ in
       };
       script = ''
         set -eu
+
+        # Copy the immutable store package into a writable app root.
+        # Symlinking would defeat Laravel's __DIR__ based path
+        # resolution: PHP's __DIR__ follows symlinks back to the
+        # read only store, breaking storage/ and bootstrap/cache/
+        # writes even when those subtrees are themselves symlinked
+        # into a writable state dir.
         rm -rf ${appRoot}
         mkdir -p ${appRoot}
-        for entry in ${cfg.backendPackage}/share/php/tide-backend/*; do
-          name="$(basename "$entry")"
-          case "$name" in
-            storage|bootstrap)
-              ;;
-            *)
-              ln -s "$entry" "${appRoot}/$name"
-              ;;
-          esac
-        done
-        # bootstrap dir: symlink everything from the store
-        # except cache/ which must be writable.
-        mkdir -p ${appRoot}/bootstrap
-        for entry in ${cfg.backendPackage}/share/php/tide-backend/bootstrap/*; do
-          name="$(basename "$entry")"
-          if [ "$name" != "cache" ]; then
-            ln -sf "$entry" "${appRoot}/bootstrap/$name"
-          fi
-        done
-        ln -sfn ${stateRoot}/bootstrap-cache ${appRoot}/bootstrap/cache
+        cp -rL ${cfg.backendPackage}/share/php/tide-backend/. ${appRoot}/
+        chmod -R u+w ${appRoot}
+
+        # Redirect the two mutable subtrees to /var/lib/tide/state
+        # so they survive activations and don't accumulate inside
+        # the disposable app root copy.
+        rm -rf ${appRoot}/storage ${appRoot}/bootstrap/cache
         ln -sfn ${stateRoot}/storage ${appRoot}/storage
+        ln -sfn ${stateRoot}/bootstrap-cache ${appRoot}/bootstrap/cache
 
         chown -R ${cfg.user}:${cfg.group} ${appRoot} ${stateRoot}
       '';