fix: CI typecheck error + standalone bind address

- Fix TS2339 in mcp-server.spec.ts (content.task access on string type)
- Default HOSTNAME=0.0.0.0 in start-standalone.sh for external access

Fixes #465, unblocks docker-publish workflow (#464)

scripts/start-standalone.sh

@@ -30,4 +30,7 @@ if [[ -d "$SOURCE_PUBLIC_DIR" ]]; then
 fi
 
 cd "$STANDALONE_DIR"
+# Next.js standalone server reads HOSTNAME to decide bind address.
+# Default to 0.0.0.0 so the server is accessible from outside the host.
+export HOSTNAME="${HOSTNAME:-0.0.0.0}"
 exec node server.js

tests/mcp-server.spec.ts

@@ -207,7 +207,7 @@ test.describe('MCP Server Integration', () => {
     test('mc_create_task creates a task', async ({ request }) => {
       const { content, isError } = await mcpTool('mc_create_task', { title: 'MCP e2e test task' })
       expect(isError).toBe(false)
-      if (content?.task?.id) taskIds.push(content.task.id)
+      if ((content as any)?.task?.id) taskIds.push((content as any).task.id)
     })
 
     test('mc_add_comment succeeds', async ({ request }) => {