feat(cmd/broker): wire config → log → store → httpserver (forgejo-mcp-broker-t37)

Final phase-1 step: the broker now starts. run() parses config, opens
the store, builds the httpserver, and blocks on signal.NotifyContext
until SIGTERM/SIGINT fires, at which point it drains through
httpserver.Run's graceful-shutdown path and closes the store.

--version is handled before config.Load so operators can inspect a
binary without providing the rest of the config. flag.ErrHelp is passed
through so -h exits 0. Config failure exits 2; runtime failure exits 1.

Integration tests build the binary once in TestMain and exercise three
acceptance scenarios against it:
- --version: prints build info, exits 0
- no config: exits nonzero with stderr listing every missing field
- full startup: /healthz returns 200 with correct JSON; SIGTERM triggers
  clean exit within 2s

Closes forgejo-mcp-broker-t37. Phase 1 complete.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cmd/broker/main.go

@@ -1,31 +1,96 @@
 // Command fjmcp-broker is an OAuth 2.1 authorization server and MCP session
-// broker that fronts forgejo-mcp. See ../../README.md and ../../docs/ for the
-// design.
+// broker that fronts forgejo-mcp. See ../../README.md and ../../docs/ for
+// the design.
 package main
 
 import (
+	"context"
+	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"os"
+	"os/signal"
+	"syscall"
 
 	"kode.naiv.no/olemd/forgejo-mcp-broker/internal/buildinfo"
+	"kode.naiv.no/olemd/forgejo-mcp-broker/internal/config"
+	"kode.naiv.no/olemd/forgejo-mcp-broker/internal/httpserver"
+	brokerlog "kode.naiv.no/olemd/forgejo-mcp-broker/internal/log"
+	"kode.naiv.no/olemd/forgejo-mcp-broker/internal/store"
+)
+
+// Exit codes follow the usual convention: 0 success, 2 config/usage, 1 runtime.
+const (
+	exitSuccess = 0
+	exitRuntime = 1
+	exitConfig  = 2
 )
 
 func main() {
-	var showVersion bool
-	flag.BoolVar(&showVersion, "version", false, "print build info and exit")
-	flag.Parse()
+	os.Exit(run(os.Args[1:], os.Stderr))
+}
 
-	if showVersion {
-		fmt.Printf("fjmcp-broker %s (rev %s, built %s)\n",
-			buildinfo.Version, buildinfo.GitRevision, buildinfo.BuildDate)
-		return
+// run is the testable entry point. Parses config, wires dependencies, and
+// blocks until the HTTP server exits or a shutdown signal arrives. Returns
+// an OS exit code.
+func run(args []string, out io.Writer) int {
+	// --version is handled before config.Load so operators can inspect a
+	// binary without providing the rest of the required config.
+	for _, a := range args {
+		if a == "--version" || a == "-version" {
+			fmt.Fprintf(out, "fjmcp-broker %s (rev %s, built %s)\n",
+				buildinfo.Version, buildinfo.GitRevision, buildinfo.BuildDate)
+			return exitSuccess
+		}
 	}
 
-	// Full startup wiring (config → log → store → httpserver) lands in
-	// forgejo-mcp-broker-t37. Until then this binary only serves --version
-	// so the bootstrap acceptance criteria can be exercised.
-	fmt.Fprintln(os.Stderr, "fjmcp-broker: runtime wiring not yet implemented (phase 1 in progress)")
-	fmt.Fprintln(os.Stderr, "Use --version to print build info.")
-	os.Exit(2)
+	cfg, err := config.Load(args, out)
+	switch {
+	case errors.Is(err, flag.ErrHelp):
+		return exitSuccess
+	case err != nil:
+		fmt.Fprintln(out, "fjmcp-broker: config error:")
+		fmt.Fprintln(out, err.Error())
+		return exitConfig
+	}
+
+	logger := brokerlog.New(out, cfg.Debug)
+	logger.Info("starting broker",
+		"listen", cfg.Listen,
+		"public_url", cfg.PublicURL,
+		"forgejo_url", cfg.ForgejoURL,
+		"store_path", cfg.StorePath,
+		"max_sessions", cfg.MaxSessions,
+		"idle_timeout", cfg.SessionIdleTimeout.String(),
+	)
+
+	// Signal handling is owned here; the HTTP server just responds to ctx
+	// cancellation. This keeps internal/httpserver free of signal coupling
+	// and makes it testable without any OS-level wiring.
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	st, err := store.Open(ctx, cfg.StorePath)
+	if err != nil {
+		logger.Error("open store", "err", err.Error())
+		return exitRuntime
+	}
+	defer func() {
+		if err := st.Close(); err != nil {
+			logger.Error("close store", "err", err.Error())
+		}
+	}()
+
+	srv := &httpserver.Server{
+		Addr:  cfg.Listen,
+		Log:   logger,
+		Store: st,
+	}
+	if err := srv.Run(ctx); err != nil {
+		logger.Error("server exit", "err", err.Error())
+		return exitRuntime
+	}
+	logger.Info("broker stopped")
+	return exitSuccess
 }