Update README and .env.example to reflect MySQL migration

The project moved from SQLite to MySQL but docs still referenced
DATABASE_DSN and old version requirements. Updated requirements,
env vars, and STATIC_DIR default to match current state.

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

.env.example

@@ -1,4 +1,8 @@
 PORT=8080
-DATABASE_DSN=walkies.db
+DB_HOST=localhost
+DB_PORT=3306
+DB_USER=root
+DB_PASSWORD=
+DB_NAME=walkies
 JWT_SECRET=change-me-in-production
-STATIC_DIR=./web/build
+STATIC_DIR=./web/dist

README.md

@@ -4,8 +4,9 @@ A web-based application for an animal shelter to manage volunteer scheduling, ti
 
 ## Requirements
 
-- [Go](https://golang.org/) 1.21+
-- [Node.js](https://nodejs.org/) 18+
+- [Go](https://golang.org/) 1.25+
+- [Node.js](https://nodejs.org/) 22+
+- [MySQL](https://www.mysql.com/) 8.0
 - [Task](https://taskfile.dev/) (`brew install go-task` or see [install docs](https://taskfile.dev/installation/))
 - [Docker](https://www.docker.com/) (optional, for containerised deployment)
 
@@ -64,8 +65,12 @@ The server is configured via environment variables:
 | Variable | Default | Description |
 |----------|---------|-------------|
 | `PORT` | `8080` | HTTP listen port |
-| `DATABASE_DSN` | `walkies.db` | SQLite file path |
+| `DB_HOST` | `localhost` | MySQL host |
+| `DB_PORT` | `3306` | MySQL port |
+| `DB_USER` | `root` | MySQL username |
+| `DB_PASSWORD` | *(empty)* | MySQL password |
+| `DB_NAME` | `walkies` | MySQL database name |
 | `JWT_SECRET` | `change-me-in-production` | HMAC signing key — **change this** |
-| `STATIC_DIR` | `./web/build` | Path to compiled React app |
+| `STATIC_DIR` | `./web/dist` | Path to compiled React app |
 
 Copy `.env.example` to `.env` to set these locally (the server reads environment variables directly; use a process manager or Docker to inject them).