fix: .dockerignore + LAN port binding

- Add .dockerignore to prevent host node_modules (GLIBC 2.38) from
  overwriting container-built binaries (GLIBC 2.36), fixing
  better-sqlite3 ERR_DLOPEN_FAILED crash
- Bind port to 0.0.0.0 for LAN access

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

.dockerignore

@@ -0,0 +1,6 @@
+node_modules
+.git
+.env
+*.md
+oikos-redesign-spec.md
+CLAUDE.md

docker-compose.yml

@@ -4,7 +4,7 @@ services:
     container_name: oikos
     restart: unless-stopped
     ports:
-      - "3000:3000"
+      - "0.0.0.0:3000:3000"
     volumes:
       - oikos_data:/data
     env_file: