feat: add Docker and Docker Compose support for all services

[PranavGadge01]

Summary

Adds full Docker and Docker Compose support across all three LensMint
services, enabling any contributor to spin up the entire stack locally
with a single command — no manual Node.js setup, no dependency conflicts,
no environment guesswork.

Motivation

Currently, setting up LensMint locally requires:

• Manually installing and configuring Node.js for three separate services
• Resolving peer dependency conflicts (as seen in issues like fix: owner-portal fails to start due to deprecated createPrivyWagmiConfig and duplicate imports #31)
• Manually creating .env files with no clear reference for what's needed
• Starting each service in a separate terminal

This PR removes all of that friction and makes the project significantly
more accessible to new contributors and GSoC applicants.

Changes

Owner Portal (owner-portal/)

• Dockerfile — multi-stage build: Node.js 18 Alpine for building the
  Vite app, then nginx Alpine to serve the static output. Keeps the final
  image small and production-appropriate.
• nginx.conf — configures nginx to support React client-side routing
  (all routes fall back to index.html) with static asset caching.
• .dockerignore — excludes node_modules, dist, .env files and logs.

Public Server (lensmint-public-server/)

• Dockerfile — Node.js 18 Alpine, installs production dependencies only,
  creates the database directory, exposes port 4000.
• .dockerignore — excludes node_modules, database files and .env.

Hardware Web3 Service (hardware-web3-service/)

• Dockerfile — Node.js 18 Alpine, installs production dependencies only,
  creates the database directory, exposes port 5000.
• .dockerignore — excludes node_modules, database files and .env.

Root Level

• docker-compose.yml — orchestrates all three services on a shared
  bridge network (lensmint-network). Database files are persisted via
  named Docker volumes so data survives container restarts. All secrets
  and config are passed via environment variables at runtime — nothing
  baked into the image.
• .env.example — single root-level template covering every environment
  variable needed across all three services, with clear comments.

Architecture

docker compose up --build
        │
        ├── owner-portal        (port 3000) — nginx serving built React app
        ├── public-server       (port 4000) — Node.js claim/QR server
        └── hardware-web3-service (port 5000) — Node.js blockchain service
                │
                └── all connected via lensmint-network bridge

Usage

# 1. Copy environment template
cp .env.example .env

# 2. Fill in your values in .env

# 3. Start everything
docker compose up --build

# Services:
# Owner Portal      → http://localhost:3000
# Public Server     → http://localhost:4000
# Web3 Service      → http://localhost:5000

# Stop everything
docker compose down

# Stop and delete volumes (clears database)
docker compose down -v

Design Decisions

• Multi-stage build for owner-portal: The builder stage uses the full
  Node.js image to compile the Vite app. The final stage uses nginx Alpine
  (~25MB) instead of Node (~150MB), keeping the image lean.
• Production deps only for backend services: Both Node.js services use
  npm install --production to exclude devDependencies from the image.
• Named volumes for databases: SQLite database files are stored in
  named Docker volumes, not bind mounts, so they persist across
  docker compose down and work cross-platform without permission issues.
• No secrets in images: All API keys, private keys and app secrets are
  injected at runtime via environment variables. The .env file is excluded
  from all images via .dockerignore.
• Shared bridge network: All services communicate over lensmint-network
  rather than exposing inter-service calls through the host.

Testing

• docker compose build completes without errors
• All three containers start with docker compose up
• Owner portal accessible at http://localhost:3000
• Public server accessible at http://localhost:4000
• Web3 service accessible at http://localhost:5000
• Containers communicate via lensmint-network
• Database persists after docker compose down and docker compose up