fix: unregister agent with sudo when config is in /root/.gpugo

Critical fix for agent unregistration during uninstall.

Problem:
When gpugo is installed with GPU_GO_TOKEN (agent mode), the install
script runs `sudo ggo agent register` which saves config to
/root/.gpugo/config/agent.yaml. During uninstall, the unregister
command was running as normal user and couldn't read root's config,
causing silent failure.

Changes:
1. Detect if agent config exists in root directories
   - Check /root/.gpugo/config/agent.yaml
   - Check /root/.config/ggo/agent.yaml

2. Run unregister with sudo if agent mode detected
   - Properly construct command with sudo
   - Handle sudo not available gracefully

3. Improved error handling
   - Capture exit code correctly
   - Show clear warnings if unregistration fails
   - Inform user they may need manual cleanup on server

4. Better command execution
   - Avoid word splitting issues with proper quoting
   - Disable set -e for unregister command using || pattern
   - Show exit code in warning message

This ensures agents are properly unregistered from the server before
removing local config files.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: andystime

scripts/uninstall.sh

@@ -260,10 +260,35 @@ unregister_from_server() {
     fi
 
     info "Unregistering agent from server (using binary at ${binary_path})..."
-    if "${binary_path}" agent unregister --force 2>/dev/null; then
+
+    # Check if agent config exists in root directory (agent mode)
+    # If so, we need to run unregister with sudo
+    local needs_sudo=false
+    if [ -f "/root/.gpugo/config/agent.yaml" ] || [ -f "/root/.config/ggo/agent.yaml" ]; then
+        needs_sudo=true
+        info "Agent config found in root directory, using sudo for unregistration"
+    fi
+
+    # Run unregister command
+    local unregister_result=0
+    if [ "${needs_sudo}" = "true" ]; then
+        SUDO=$(get_sudo)
+        if [ -n "${SUDO}" ]; then
+            ${SUDO} "${binary_path}" agent unregister --force 2>/dev/null || unregister_result=$?
+        else
+            warn "Sudo not available, attempting unregister without sudo (may fail)"
+            "${binary_path}" agent unregister --force 2>/dev/null || unregister_result=$?
+        fi
+    else
+        "${binary_path}" agent unregister --force 2>/dev/null || unregister_result=$?
+    fi
+
+    if [ ${unregister_result} -eq 0 ]; then
         info "Agent unregistered from server"
     else
-        warn "Server unregistration failed, local config will still be removed"
+        warn "Server unregistration failed (exit code: ${unregister_result})"
+        warn "Local config will still be removed"
+        warn "You may need to manually remove the agent from the server dashboard"
     fi
 }