config: drop go-toml and the legacy TOML migrations

The one-shot config.toml -> config.ini and books.toml -> books.ini
migrations (a transition aid from the pre-INI format) are removed, along
with the github.com/pelletier/go-toml/v2 dependency and the now-dead
`toml:` struct tags. The live config format has been INI for many
releases; anyone still on a .toml recreates it (the format is
self-documenting on first run). Leaves 3 direct deps, all in active use
(bubbletea, lipgloss, go-pdf/fpdf). Tests updated to write INI.

1 files changed, 12 insertions, 34 deletions

diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index dd75808..4d172c0 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -68,8 +68,8 @@ func TestLoadOverride(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
 	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("offline = true\ndefault_version = \"wuj\"\n"), 0o644)
+	os.WriteFile(filepath.Join(dir, "lectio", "config.ini"),
+		[]byte("offline = true\ndefault_version = wuj\n"), 0o644)
 	cfg, _ := Load()
 	if !cfg.Offline || cfg.DefaultVersion != "wuj" {
 		t.Errorf("override not applied: %+v", cfg)
@@ -121,8 +121,8 @@ func TestWebDisplayLoadsSetting(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
 	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("web_display = \"vertical\"\n"), 0o644)
+	os.WriteFile(filepath.Join(dir, "lectio", "config.ini"),
+		[]byte("web_display = vertical\n"), 0o644)
 	cfg, err := Load()
 	if err != nil {
 		t.Fatal(err)
@@ -136,8 +136,8 @@ func TestWebDisplayNormalizesUnknown(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
 	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("web_display = \"bogus\"\n"), 0o644)
+	os.WriteFile(filepath.Join(dir, "lectio", "config.ini"),
+		[]byte("web_display = bogus\n"), 0o644)
 	cfg, err := Load()
 	if err != nil {
 		t.Fatal(err)
@@ -158,8 +158,8 @@ func TestUILanguageLoadsPL(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
 	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("ui_language = \"pl\"\n"), 0o644)
+	os.WriteFile(filepath.Join(dir, "lectio", "config.ini"),
+		[]byte("ui_language = pl\n"), 0o644)
 	cfg, err := Load()
 	if err != nil {
 		t.Fatal(err)
@@ -176,8 +176,8 @@ func TestUILanguagePreservesAnyCode(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
 	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("ui_language = \"FR\"\n"), 0o644)
+	os.WriteFile(filepath.Join(dir, "lectio", "config.ini"),
+		[]byte("ui_language = FR\n"), 0o644)
 	cfg, err := Load()
 	if err != nil {
 		t.Fatal(err)
@@ -210,8 +210,8 @@ func TestPagerLoadsSetting(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
 	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("pager = \"less -R\"\n"), 0o644)
+	os.WriteFile(filepath.Join(dir, "lectio", "config.ini"),
+		[]byte("pager = less -R\n"), 0o644)
 	cfg, err := Load()
 	if err != nil {
 		t.Fatal(err)
@@ -303,28 +303,6 @@ func TestUseLayers(t *testing.T) {
 	}
 }
 
-func TestMigrateTOMLToINI(t *testing.T) {
-	dir := t.TempDir()
-	t.Setenv("XDG_CONFIG_HOME", dir)
-	os.MkdirAll(filepath.Join(dir, "lectio"), 0o755)
-	// only the old TOML exists -> Load converts once and writes config.ini.
-	os.WriteFile(filepath.Join(dir, "lectio", "config.toml"),
-		[]byte("ui_language = \"pl\"\ndefault_version = \"wuj\"\n"), 0o644)
-	cfg, err := Load()
-	if err != nil {
-		t.Fatal(err)
-	}
-	if cfg.UILanguage != "pl" || cfg.DefaultVersion != "wuj" {
-		t.Errorf("migrated values wrong: %+v", cfg)
-	}
-	if _, err := os.Stat(filepath.Join(dir, "lectio", "config.ini")); err != nil {
-		t.Error("config.ini not written on migration")
-	}
-	if _, err := os.Stat(filepath.Join(dir, "lectio", "config.toml")); err != nil {
-		t.Error("old config.toml should be kept (reversible)")
-	}
-}
-
 func TestPartShown(t *testing.T) {
 	var empty Config
 	if !empty.PartShown("new", "psalm") {