fix: instance completions use server.name, smart attach/detach

- Instances have no name field — use server.name for completions
- attach-server: show only servers NOT in the project
- detach-server: show only servers IN the project
- Add helper functions for project-aware server completion
- 5 new tests covering all three fixes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

completions/mcpctl.bash

@@ -55,10 +55,26 @@ _mcpctl() {
   _mcpctl_resource_names() {
     local rt="$1"
     if [[ -n "$rt" ]]; then
-      mcpctl get "$rt" -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
+      # Instances don't have a name field — use server.name instead
+      if [[ "$rt" == "instances" ]]; then
+        mcpctl get instances -o json 2>/dev/null | jq -r '.[][].server.name' 2>/dev/null
+      else
+        mcpctl get "$rt" -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
+      fi
     fi
   }
 
+  # Get the --project value from the command line
+  _mcpctl_get_project_value() {
+    local i
+    for ((i=1; i < cword; i++)); do
+      if [[ "${words[i]}" == "--project" ]] && (( i+1 < cword )); then
+        echo "${words[i+1]}"
+        return
+      fi
+    done
+  }
+
   case "$subcmd" in
     config)
       if [[ $((cword - subcmd_pos)) -eq 1 ]]; then
@@ -108,9 +124,24 @@ _mcpctl() {
     restore)
       COMPREPLY=($(compgen -W "-i --input -p --password -c --conflict -h --help" -- "$cur"))
       return ;;
-    attach-server|detach-server)
-      local names
-      names=$(_mcpctl_resource_names "servers")
+    attach-server)
+      local proj names all_servers proj_servers
+      proj=$(_mcpctl_get_project_value)
+      if [[ -n "$proj" ]]; then
+        all_servers=$(mcpctl get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null)
+        proj_servers=$(mcpctl --project "$proj" get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null)
+        names=$(comm -23 <(echo "$all_servers" | sort) <(echo "$proj_servers" | sort))
+      else
+        names=$(_mcpctl_resource_names "servers")
+      fi
+      COMPREPLY=($(compgen -W "$names" -- "$cur"))
+      return ;;
+    detach-server)
+      local proj names
+      proj=$(_mcpctl_get_project_value)
+      if [[ -n "$proj" ]]; then
+        names=$(mcpctl --project "$proj" get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null)
+      fi
       COMPREPLY=($(compgen -W "$names" -- "$cur"))
       return ;;
     help)