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.

db/db.go

@@ -1,33 +1,70 @@
+// Package db handles SQLite database setup, pragma configuration, and
+// goose migrations.
 package db
 
 import (
 	"database/sql"
 	"embed"
+	"errors"
+	"fmt"
+	"io/fs"
+	"log/slog"
+	"os"
+	"path/filepath"
 
 	"github.com/pressly/goose/v3"
 	_ "modernc.org/sqlite"
 )
 
 //go:embed migrations/*.sql
-var migrations embed.FS
+var MigrationFS embed.FS
 
 var DB *sql.DB
 
-func Init(dbPath string) error {
+func Init(dbPath string) (func(), error) {
+	if err := os.MkdirAll(filepath.Dir(dbPath), 0o755); err != nil {
+		return nil, fmt.Errorf("creating data dir: %w", err)
+	}
+
+	// busy_timeout must be first because the connection needs to block on
+	// busy before WAL mode is set in case it hasn't been set already.
+	pragmas := "?_pragma=busy_timeout(10000)&_pragma=journal_mode(WAL)&_pragma=journal_size_limit(200000000)&_pragma=synchronous(NORMAL)&_pragma=foreign_keys(ON)&_pragma=temp_store(MEMORY)&_pragma=cache_size(-32000)"
 	var err error
-	DB, err = sql.Open("sqlite", dbPath+"?_journal_mode=WAL&_busy_timeout=5000")
+	DB, err = goose.OpenDBWithDriver("sqlite", dbPath+pragmas)
 	if err != nil {
-		return err
+		return nil, fmt.Errorf("opening database: %w", err)
 	}
-	DB.SetMaxOpenConns(1)
 
-	goose.SetBaseFS(migrations)
+	if err := DB.Ping(); err != nil {
+		return nil, errors.Join(fmt.Errorf("pinging database: %w", err), DB.Close())
+	}
+	slog.Info("db connected", "db", dbPath)
+
+	sub, err := fs.Sub(MigrationFS, "migrations")
+	if err != nil {
+		return nil, errors.Join(fmt.Errorf("migrations sub fs: %w", err), DB.Close())
+	}
+	goose.SetBaseFS(sub)
+
 	if err := goose.SetDialect("sqlite3"); err != nil {
-		return err
+		return nil, errors.Join(fmt.Errorf("setting goose dialect: %w", err), DB.Close())
 	}
-	if err := goose.Up(DB, "migrations"); err != nil {
-		return err
+	if err := goose.Up(DB, "."); err != nil {
+		return nil, errors.Join(fmt.Errorf("running migrations: %w", err), DB.Close())
 	}
 
-	return nil
+	if _, err := DB.Exec("PRAGMA optimize"); err != nil {
+		return nil, errors.Join(fmt.Errorf("pragma optimize: %w", err), DB.Close())
+	}
+
+	cleanup := func() {
+		if _, err := DB.Exec("PRAGMA optimize(0x10002)"); err != nil {
+			slog.Error("pragma optimize at shutdown", "error", err)
+		}
+		if err := DB.Close(); err != nil {
+			slog.Error("closing database", "error", err)
+		}
+	}
+
+	return cleanup, nil
 }