refactor: switch the whole project to English

talk is going to be published. Code comments, CLI output, error messages,
daemon log lines, MCP descriptions and results, test names and assertions,
README, spec, skill, build scripts and flake are now English. Only the
spoken announcement texts stay bilingual: the wrap result and the test
sentence are German or English depending on the detected language.

Language fallback is now configurable: `lang = "en" | "de"` (env
TALK_LANG, default en) is used when detection cannot tell (numbers, single
words, ties) and for talk's own announcements. langdetect.Detect takes the
fallback as an argument instead of hard-coding German. `talk setup` asks for
it; `talk doctor` and `talk status` show it.

Vocabulary pinned across packages so the process-boundary tests observe
stable strings: chain log lines ("chain: tier X skipped (not available)",
"falling back to the next tier", "spoken via X"), queue lines ("discarded:
quiet hours ... active", "replaced by toast", "max_age"), CLI notes
("speaking directly", "daemon started at", "no daemon", "nothing to cancel"),
status block with aligned English labels, MCP messages, origin guard 403.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/provider/voices_test.go

@@ -2,9 +2,9 @@ package provider
 
 import "testing"
 
-// TestResolveVoiceRangfolge pinnt die dokumentierte Rangfolge
-// --voice-Pin > config-Mapping > Repo-Default > en-Default.
-func TestResolveVoiceRangfolge(t *testing.T) {
+// TestResolveVoicePrecedence pins the documented precedence
+// --voice pin > config mapping > repo default > en default.
+func TestResolveVoicePrecedence(t *testing.T) {
 	cases := []struct {
 		name     string
 		provider string
@@ -13,14 +13,14 @@ func TestResolveVoiceRangfolge(t *testing.T) {
 		cfg      map[string]string
 		want     string
 	}{
-		{"Default edge de", "edge", "de", "", nil, "de-DE-KatjaNeural"},
-		{"Default edge en", "edge", "en", "", nil, "en-US-AriaNeural"},
-		{"Default elevenlabs de (neutral, nicht privat)", "elevenlabs", "de", "", nil, "21m00Tcm4TlvDq8ikWAM"},
-		{"Default openai en", "openai", "en", "", nil, "alloy"},
-		{"Mapping schlägt Default", "edge", "de", "", map[string]string{"de": "de-DE-ConradNeural"}, "de-DE-ConradNeural"},
-		{"Pin schlägt Mapping", "edge", "de", "Gepinnt", map[string]string{"de": "de-DE-ConradNeural"}, "Gepinnt"},
-		{"unbekannte Sprache → en-Default", "edge", "fr", "", nil, "en-US-AriaNeural"},
-		{"osbuiltin kennt keine Voice-IDs", "osbuiltin", "de", "", nil, ""},
+		{"default edge de", "edge", "de", "", nil, "de-DE-KatjaNeural"},
+		{"default edge en", "edge", "en", "", nil, "en-US-AriaNeural"},
+		{"default elevenlabs de (neutral, not private)", "elevenlabs", "de", "", nil, "21m00Tcm4TlvDq8ikWAM"},
+		{"default openai en", "openai", "en", "", nil, "alloy"},
+		{"mapping beats default", "edge", "de", "", map[string]string{"de": "de-DE-ConradNeural"}, "de-DE-ConradNeural"},
+		{"pin beats mapping", "edge", "de", "Pinned", map[string]string{"de": "de-DE-ConradNeural"}, "Pinned"},
+		{"unknown language falls back to en default", "edge", "fr", "", nil, "en-US-AriaNeural"},
+		{"osbuiltin has no voice IDs", "osbuiltin", "de", "", nil, ""},
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {