Change docker go cache dir to _working

This was previously breaking the go tooling as the working directly was
being searched by the lsp and go mod tidy. The go tools ignore
directories that begin with underscores.

.dockerignore

@@ -1,2 +1,2 @@
 *.toml
-working
+_working

.gitignore

@@ -1,3 +1,3 @@
-working
+_working
 server
 server.toml

docker/docker-compose.yml

@@ -10,4 +10,4 @@ services:
       - "..:/build"
       - "../server.toml:/root/.config/cursorius/server.toml"
       - "/var/run/docker.sock:/var/run/docker.sock"
-      - "../working/go:/go-src"
+      - "../_working/go:/go"

docker/run-dev.sh

@@ -2,7 +2,7 @@
 
 set -e
 
-mkdir -p working
+mkdir -p _working
 
 case $1 in
     "default")