feat: add admin publishing workflow and yar theme

Add Go/Postgres admin APIs, Angular admin UI, manual build flow, asset uploads, markdown import/export, configurable slug generation, and the Yar reading theme. Exclude local docs and generated development artifacts from version control.

backend/cmd/import-articles/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"osaet/backend/internal/postimport"
+)
+
+func main() {
+	fs := flag.NewFlagSet("import-articles", flag.ExitOnError)
+	file := fs.String("file", "articles.csv", "CSV file path")
+	overwrite := fs.Bool("overwrite", false, "overwrite existing markdown files")
+	postsDir := fs.String("posts-dir", "content/posts", "posts output directory relative to project root")
+	if err := fs.Parse(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "error:", err)
+		os.Exit(1)
+	}
+
+	result, err := postimport.Import(postimport.Options{
+		CSVPath:    *file,
+		PostsDir:   *postsDir,
+		Overwrite:  *overwrite,
+		WorkingDir: "",
+	})
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "error:", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("imported %d post(s), skipped %d existing file(s), skipped %d non-post row(s)\n", result.Imported, result.SkippedExisting, result.SkippedNonPost)
+}

backend/cmd/osaet-admin/main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"osaet/backend/internal/admin"
+)
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Fprintln(os.Stderr, "error:", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	command := "serve"
+	if len(os.Args) > 1 {
+		command = os.Args[1]
+	}
+
+	cfg := admin.LoadConfig()
+	if err := cfg.Validate(); err != nil {
+		return err
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	db, err := admin.OpenDatabase(ctx, cfg.DatabaseURL)
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+
+	switch command {
+	case "serve":
+		return serve(ctx, cfg, db)
+	case "migrate":
+		return admin.RunMigrations(ctx, db, cfg.MigrationsDir)
+	case "create-user":
+		return createUser(ctx, db)
+	case "import-markdown":
+		return importMarkdown(ctx, cfg, db)
+	default:
+		return fmt.Errorf("unknown command %q", command)
+	}
+}
+
+func createUser(ctx context.Context, db *pgxpool.Pool) error {
+	if len(os.Args) < 3 {
+		return errors.New("usage: osaet-admin create-user <username>")
+	}
+
+	password := os.Getenv("OSAET_ADMIN_PASSWORD")
+	if password == "" {
+		return errors.New("OSAET_ADMIN_PASSWORD is required")
+	}
+
+	user, err := admin.NewStore(db).CreateOrUpdateUser(ctx, os.Args[2], password)
+	if err != nil {
+		return err
+	}
+
+	fmt.Fprintf(os.Stdout, "admin user %q is ready\n", user.Username)
+	return nil
+}
+
+func importMarkdown(ctx context.Context, cfg admin.Config, db *pgxpool.Pool) error {
+	postsDir := cfg.PostsDir
+	if len(os.Args) >= 3 {
+		postsDir = os.Args[2]
+	}
+
+	result, err := admin.NewStore(db).ImportMarkdownPosts(ctx, postsDir)
+	if err != nil {
+		return err
+	}
+
+	fmt.Fprintf(os.Stdout, "imported %d markdown post(s), skipped %d file(s)\n", result.Imported, result.Skipped)
+	return nil
+}
+
+func serve(ctx context.Context, cfg admin.Config, db *pgxpool.Pool) error {
+	server := &http.Server{
+		Addr:              cfg.Addr,
+		Handler:           admin.NewServerWithContext(ctx, db, cfg).Router(),
+		ReadHeaderTimeout: 5 * time.Second,
+	}
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- server.ListenAndServe()
+	}()
+
+	select {
+	case <-ctx.Done():
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+		return server.Shutdown(shutdownCtx)
+	case err := <-errCh:
+		if errors.Is(err, http.ErrServerClosed) {
+			return nil
+		}
+		return err
+	}
+}