feat: books.toml -> books.ini, multi-language (add Latin dialect), config-scoped citation display

books.ini with [en]/[pl]/[la]; parseBooks reads INI (bible drops go-toml).
Latin dialect resolves EF citations (Eccli->Sirach, Apoc->Revelation, Luc...);
sigla_style gains 'latin'. Reading citations now DISPLAY in the configured
sigla (FormatRef(SiglaLang)), not raw English. One-shot books.toml->books.ini
user migration (go-toml now config-only). Web settings editor -> books.ini.

1 files changed, 65 insertions, 9 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index 54185d1..8d2ddca 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -38,7 +38,7 @@ const configHeader = `# lectio configuration (INI). Full-line comments only (# o
 #   all               true | false             (all readings, or just the gospel)
 #   offline           true | false             (never fetch; cache/sigla only)
 #   ui_language       en | pl                  (interface chrome; readings stay source-language)
-#   sigla_style       auto | polish | english  (citation dialect; auto follows ui_language)
+#   sigla_style       auto | polish | english | latin  (citation dialect; auto follows ui_language)
 #   web_theme         a theme name (see docs/THEMES.md)
 #   web_port          integer; 0 = try 1099, then any free port
 #   web_display       horizontal | vertical | interlinear
@@ -135,6 +135,8 @@ func NormalizeSiglaStyle(s string) string {
 	switch strings.ToLower(strings.TrimSpace(s)) {
 	case "polish", "pl":
 		return "polish"
+	case "latin", "la":
+		return "latin"
 	case "english", "en":
 		return "english"
 	default:
@@ -190,6 +192,8 @@ func (c Config) SiglaLang() string {
 	switch c.SiglaStyle {
 	case "polish":
 		return "pl"
+	case "latin":
+		return "la"
 	case "english":
 		return "en"
 	default:
@@ -270,7 +274,7 @@ func CalendarsDir() (string, error) {
 	return filepath.Join(filepath.Dir(p), "calendars"), nil
 }
 
-// BooksPath returns the path to the optional user books.toml (in the same
+// BooksPath returns the path to the optional user books.ini (in the same
 // directory as the config file). There is no embedded seed on disk -- absence
 // means "use the built-in defaults".
 func BooksPath() (string, error) {
@@ -278,22 +282,74 @@ func BooksPath() (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return filepath.Join(filepath.Dir(p), "books.toml"), nil
+	return filepath.Join(filepath.Dir(p), "books.ini"), nil
 }
 
-// UserBooksTOML returns the bytes of the optional user books.toml (see
-// BooksPath), or nil when it is absent or unreadable -- callers then fall back
-// to bible's embedded default table.
-func UserBooksTOML() []byte {
+// UserBooksINI returns the bytes of the optional user books.ini (see BooksPath),
+// or nil when absent/unreadable -- callers then fall back to bible's embedded
+// default table. A former books.toml at the same location is converted to
+// books.ini once, on first read (the old file is kept).
+func UserBooksINI() []byte {
 	p, err := BooksPath()
 	if err != nil {
 		return nil
 	}
-	b, err := os.ReadFile(p)
+	if b, err := os.ReadFile(p); err == nil {
+		return b
+	}
+	tomlPath := filepath.Join(filepath.Dir(p), "books.toml")
+	data, err := os.ReadFile(tomlPath)
 	if err != nil {
 		return nil
 	}
-	return b
+	out := booksTOMLtoINI(data)
+	if out == nil {
+		return nil
+	}
+	_ = os.WriteFile(p, out, 0o644)
+	fmt.Fprintf(os.Stderr, "lectio: migrated %s -> books.ini (old file kept)\n", tomlPath)
+	return out
+}
+
+// booksTOMLtoINI converts a former books.toml (dialect -> book -> [forms]) into
+// books.ini. Returns nil if the TOML is unparseable.
+func booksTOMLtoINI(data []byte) []byte {
+	var raw map[string]map[string][]string
+	if err := toml.Unmarshal(data, &raw); err != nil {
+		return nil
+	}
+	var b strings.Builder
+	b.WriteString("# lectio book names & abbreviations, per dialect (migrated from books.toml).\n")
+	emit := func(d string) {
+		books := raw[d]
+		if books == nil {
+			return
+		}
+		fmt.Fprintf(&b, "\n[%s]\n", d)
+		keys := make([]string, 0, len(books))
+		for k := range books {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		for _, k := range keys {
+			fmt.Fprintf(&b, "%s = %s\n", k, strings.Join(books[k], ", "))
+		}
+	}
+	seen := map[string]bool{"en": true, "pl": true, "la": true}
+	emit("en")
+	emit("pl")
+	emit("la")
+	others := make([]string, 0)
+	for d := range raw {
+		if !seen[d] {
+			others = append(others, d)
+		}
+	}
+	sort.Strings(others)
+	for _, d := range others {
+		emit(d)
+	}
+	return []byte(b.String())
 }
 
 // seedIfMissing writes the embedded default config to path if nothing is