ki18n: add gettext CI check for missing translation keys

gettext now exits 1 when any key extracted from templates is absent from
a locale file. Added as a task and wired into the check task.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 17 insertions, 3 deletions

diff --git a/README.md b/README.md
index 9e6cf5a..aa436a4 100644
--- a/README.md
+++ b/README.md
@@ -15,14 +15,17 @@
 
 ## ki18n
 
-- [ ] Add gettext to CI
-
 ### Setup
 
 1. Call `ki18n.Init(localesFS)` at startup with a filesystem containing `<lang>/*.yml` translation files. Pass extra `ki18n.Locale` values to register additional languages.
 2. Register `ki18n.LangMiddleware(...)` on your router, passing one or more strategies in priority order.
-3. Run `go run github.com/martinlehoux/kagamigo/cmd/gettext -write` to generate translation files.
+3. Run `go run github.com/martinlehoux/kagamigo/ki18n/cmd/gettext -write` to generate translation files.
 4. Complete the generated files.
+5. Add the check to CI — exits 1 if any translation key is missing from a locale file:
+
+```sh
+go run github.com/martinlehoux/kagamigo/ki18n/cmd/gettext
+```
 
 ### Language detection strategies
 
diff --git a/Taskfile.yml b/Taskfile.yml
index 0ba1f5f..7033429 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -6,6 +6,10 @@ tasks:
     cmds:
       - go tool templ generate
 
+  gettext:
+    cmds:
+      - go run github.com/martinlehoux/kagamigo/ki18n/cmd/gettext
+
   check:
     cmds:
       - gofmt -d -e -s .
@@ -17,6 +21,7 @@ tasks:
       - go test -race ./...
       - go tool revive
       - go mod tidy
+      - task gettext
 
   tools:
     cmds:
diff --git a/ki18n/cmd/gettext/gettext.go b/ki18n/cmd/gettext/gettext.go
index e68dd22..b3b47cd 100644
--- a/ki18n/cmd/gettext/gettext.go
+++ b/ki18n/cmd/gettext/gettext.go
@@ -174,6 +174,7 @@ func main() {
 	extractedKeys := extractAllKeys()
 	baseLogger.Info("extracted keys from templates", slog.Int("count", len(extractedKeys)))
 
+	missingKeys := false
 	for _, lang := range langs {
 		logger := baseLogger.With(slog.String("lang", lang))
 		currentLocales := getOrCreateLocale(lang, logger)
@@ -201,6 +202,7 @@ func main() {
 			if _, ok := currentLocales[key]; !ok {
 				logger.Info(`found missing key`, slog.String("key", key))
 				newLocales[key] = ""
+				missingKeys = true
 			}
 		}
 		var completion string
@@ -217,4 +219,8 @@ func main() {
 			kcore.Expect(os.WriteFile(filepath.Join("locales", lang, "index.yml"), content, 0o600), "error writing file")
 		}
 	}
+
+	if missingKeys {
+		os.Exit(1)
+	}
 }