refactor: adopt portigo infrastructure patterns

Add config package with build-tag-switched dev/prod environments,
structured logging via zerolog, Taskfile for dev workflow, golangci-lint
config, testutil package, and improved DB setup with proper SQLite
pragmas and cleanup. Rename sqlc output package from gen to repository.

Switch to allowlist .gitignore, Alpine+UPX+scratch Dockerfile, and
CI pipeline with test/lint gates before deploy.

logging/log.go

@@ -0,0 +1,41 @@
+// Package logging configures zerolog and provides HTTP request logging middleware.
+package logging
+
+import (
+	"io"
+	stdlog "log"
+	"os"
+
+	"github.com/ryanhamamura/c4/config"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"github.com/rs/zerolog/pkgerrors"
+)
+
+func SetupLogger(env config.Environment, level zerolog.Level) *zerolog.Logger {
+	zerolog.ErrorStackFieldName = "stack_trace"
+	zerolog.ErrorStackMarshaler = pkgerrors.MarshalStack
+
+	zerolog.SetGlobalLevel(level)
+	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+	var output io.Writer
+	switch env {
+	case config.Dev:
+		output = zerolog.ConsoleWriter{
+			Out:        os.Stderr,
+			TimeFormat: "2006/01/02 15:04:05",
+		}
+	case config.Prod:
+		output = os.Stderr
+	}
+
+	logger := zerolog.New(output).With().Timestamp().Stack().Logger()
+	zerolog.DefaultContextLogger = &logger
+	log.Logger = logger
+
+	stdlog.SetFlags(0)
+	stdlog.SetOutput(logger)
+	return &logger
+}

logging/middleware.go

@@ -0,0 +1,126 @@
+package logging
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/ryanhamamura/c4/config"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+const (
+	ansiReset         = "\033[0m"
+	ansiBrightRed     = "\033[31;1m"
+	ansiBrightGreen   = "\033[32;1m"
+	ansiBrightYellow  = "\033[33;1m"
+	ansiBrightMagenta = "\033[35;1m"
+	ansiBrightCyan    = "\033[36;1m"
+	ansiGreen         = "\033[32m"
+	ansiYellow        = "\033[33m"
+	ansiRed           = "\033[31m"
+)
+
+func colorStatus(status int, useColor bool) string {
+	s := fmt.Sprintf("%d", status)
+	if !useColor {
+		return s
+	}
+	switch {
+	case status < 200:
+		return ansiBrightGreen + s + ansiReset
+	case status < 300:
+		return ansiBrightGreen + s + ansiReset
+	case status < 400:
+		return ansiBrightCyan + s + ansiReset
+	case status < 500:
+		return ansiBrightYellow + s + ansiReset
+	default:
+		return ansiBrightRed + s + ansiReset
+	}
+}
+
+func colorMethod(method string, useColor bool) string {
+	if !useColor {
+		return method
+	}
+	return ansiBrightMagenta + method + ansiReset
+}
+
+func colorLatency(d time.Duration, useColor bool) string {
+	s := d.String()
+	if !useColor {
+		return s
+	}
+	switch {
+	case d < 500*time.Millisecond:
+		return ansiGreen + s + ansiReset
+	case d < 5*time.Second:
+		return ansiYellow + s + ansiReset
+	default:
+		return ansiRed + s + ansiReset
+	}
+}
+
+type responseWriter struct {
+	http.ResponseWriter
+	status int
+}
+
+func (rw *responseWriter) WriteHeader(code int) {
+	rw.status = code
+	rw.ResponseWriter.WriteHeader(code)
+}
+
+func RequestLogger(logger *zerolog.Logger, env config.Environment) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			start := time.Now()
+			rw := &responseWriter{ResponseWriter: w}
+
+			next.ServeHTTP(rw, r)
+
+			status := rw.status
+			if status == 0 {
+				status = http.StatusOK
+			}
+			l := log.Ctx(r.Context())
+			if l.GetLevel() == zerolog.Disabled {
+				l = logger
+			}
+
+			var evt *zerolog.Event
+			switch {
+			case status < 400:
+				evt = l.Info()
+			case status < 500:
+				evt = l.Warn()
+			case status < 600:
+				evt = l.Error()
+			default:
+				evt = l.Info()
+			}
+
+			latency := time.Since(start)
+			switch env {
+			case config.Dev:
+				useColor := true
+				evt.Msg(fmt.Sprintf("%s %s %s [%s]",
+					colorStatus(status, useColor),
+					colorMethod(r.Method, useColor),
+					r.URL.Path,
+					colorLatency(latency, useColor),
+				))
+			default:
+				evt.
+					Int("status", status).
+					Str("method", r.Method).
+					Str("path", r.URL.Path).
+					Dur("latency", latency).
+					Msg("request")
+			}
+		})
+	}
+}