Track cmd/email-agent/main.go (fix .gitignore shadowing)

The unanchored `email-agent` ignore rule matched the `cmd/email-agent/`
directory as well as the root build artifact, so the service entry point was
never committed and a fresh clone could not build. Anchor the rule to the repo
root (`/email-agent`).

This completes the Phase 1.1 tracked tree (AUD-58): entry point, config, SQLite
store, HTTP server, Dockerfile and compose.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.gitignore

@@ -13,7 +13,8 @@ bin/
 
 # Local runtime data (SQLite)
 data/
-email-agent
+# Compiled binary at the repo root only. Must NOT match cmd/email-agent/.
+/email-agent
 
 # Python
 __pycache__/

cmd/email-agent/main.go

@@ -0,0 +1,117 @@
+// Command email-agent runs the Email Agent HTTP service.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"gitea.lab.audasmedia.com.au/sam/email_agent/internal/config"
+	"gitea.lab.audasmedia.com.au/sam/email_agent/internal/server"
+	"gitea.lab.audasmedia.com.au/sam/email_agent/internal/store"
+	"gitea.lab.audasmedia.com.au/sam/email_agent/internal/version"
+)
+
+func main() {
+	var (
+		showVersion = flag.Bool("version", false, "print version information and exit")
+		healthcheck = flag.Bool("healthcheck", false, "probe the local /health endpoint and exit")
+	)
+	flag.Parse()
+
+	if *showVersion {
+		fmt.Printf("email-agent %s (commit %s)\n", version.Version, version.Commit)
+		return
+	}
+
+	cfg, err := config.Load()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "config error: %v\n", err)
+		os.Exit(1)
+	}
+
+	logger := newLogger(cfg.LogLevel)
+	slog.SetDefault(logger)
+
+	if *healthcheck {
+		if err := probeHealth(cfg.Port); err != nil {
+			fmt.Fprintf(os.Stderr, "healthcheck failed: %v\n", err)
+			os.Exit(1)
+		}
+		return
+	}
+
+	if err := run(cfg, logger); err != nil {
+		logger.Error("fatal", "error", err)
+		os.Exit(1)
+	}
+}
+
+func run(cfg *config.Config, logger *slog.Logger) error {
+	logger.Info("starting email-agent",
+		"version", version.Version,
+		"commit", version.Commit,
+		"env", cfg.Env,
+	)
+
+	if cfg.SessionSecret == "" {
+		logger.Warn("EMAIL_AGENT_SESSION_SECRET is not set; set it before enabling login")
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	st, err := store.Open(ctx, cfg.DBPath)
+	if err != nil {
+		return fmt.Errorf("open store: %w", err)
+	}
+	defer func() {
+		if cerr := st.Close(); cerr != nil {
+			logger.Error("close store", "error", cerr)
+		}
+	}()
+
+	schemaVersion, err := st.SchemaVersion(ctx)
+	if err != nil {
+		return fmt.Errorf("read schema version: %w", err)
+	}
+	logger.Info("database ready", "path", st.Path(), "schema_version", schemaVersion)
+
+	srv, err := server.New(cfg, st, logger)
+	if err != nil {
+		return fmt.Errorf("build server: %w", err)
+	}
+
+	return srv.Run(ctx)
+}
+
+// probeHealth requests the local health endpoint. It exists so the container
+// healthcheck does not need an external HTTP client in the image.
+func probeHealth(port int) error {
+	client := &http.Client{Timeout: 3 * time.Second}
+	url := fmt.Sprintf("http://127.0.0.1:%d/health", port)
+	resp, err := client.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("unexpected status %d from %s", resp.StatusCode, url)
+	}
+	return nil
+}
+
+func newLogger(level string) *slog.Logger {
+	var lvl slog.Level
+	if err := lvl.UnmarshalText([]byte(level)); err != nil {
+		lvl = slog.LevelInfo
+	}
+	handler := slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: lvl})
+	return slog.New(handler)
+}