docs: add usage and verify build

README.md

@@ -0,0 +1,24 @@
+# email-mcp
+
+`email-mcp` is a local Go CLI for configuring one IMAP account in KDE Wallet and exposing read-only mailbox access over MCP.
+
+## Requirements
+
+- Linux
+- A D-Bus session with KDE Wallet available
+- Go 1.25 or newer
+- IMAP account credentials
+
+## Commands
+
+- `email-mcp setup` to store IMAP credentials
+- `email-mcp mcp` to start the MCP stdio server
+
+If you build the binary locally from this repo, run it as `./email-mcp` from the project root.
+
+## Build and Test
+
+```bash
+go test ./...
+go build ./cmd/email-mcp
+```