feat(i18n): add translations for zh-Hans, de, fr, es, ja, pt-BR

Ships first-pass AI translations for six locales on top of the existing
English base, plus a simple JSON-per-locale contributor workflow so new
languages can land as a single PR.

- 518 keys translated per locale (proper nouns / brand names / format-
  only strings left to fall back to English by design — see the
  "Non-blocking (intentional verbatim)" section of scarf/docs/I18N.md).
- Per-locale source-of-truth lives in tools/translations/<locale>.json;
  tools/merge-translations.py writes them into Localizable.xcstrings
  and is idempotent (re-runnable as translators iterate).
- InfoPlist.xcstrings (macOS microphone permission prompt) translated
  for all six locales.
- knownRegions expanded: zh-Hans, de, fr now join by es, ja, pt-BR.
- CONTRIBUTING.md gains an "Adding a Language" section documenting the
  fork → JSON → merge → PR flow. Native-speaker reviews welcome.

Closes #13 (the original ask: Simplified Chinese support).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scarf/docs/I18N.md

@@ -7,12 +7,27 @@ Scarf uses Apple's modern **String Catalog** workflow. Source strings are auto-e
 | Locale | Status |
 |---|---|
 | `en` (English) | Base / source |
-| `zh-Hans` (Simplified Chinese) | Region enabled, translations pending |
-| `de` (German) | Region enabled, translations pending |
-| `fr` (French) | Region enabled, translations pending |
+| `zh-Hans` (Simplified Chinese) | AI-translated, native-speaker review welcome |
+| `de` (German) | AI-translated, native-speaker review welcome |
+| `fr` (French) | AI-translated, native-speaker review welcome |
+| `es` (Spanish) | AI-translated, native-speaker review welcome |
+| `ja` (Japanese) | AI-translated, native-speaker review welcome |
+| `pt-BR` (Portuguese, Brazil) | AI-translated, native-speaker review welcome |
 
 Canadian French users are served by base `fr`. `fr-CA` will be added only if a concrete Québec-specific bug is reported.
 
+### Translation workflow
+
+Source-of-truth per locale lives in `tools/translations/<locale>.json` — a flat `{ "English": "Translation" }` map. The merge step writes those into `scarf/scarf/Localizable.xcstrings` via:
+
+```bash
+python3 tools/merge-translations.py
+```
+
+Keys absent from a locale file fall back to English at runtime — this is deliberate for proper nouns (Scarf, Hermes, Anthropic, OAuth, SSH…) and format-only strings (`%lld`, `%@ → %@`, `•`). Re-running the merge is idempotent; iterate on a JSON and re-merge.
+
+Contributor path for new languages is documented in the repo root [CONTRIBUTING.md](../../CONTRIBUTING.md#adding-a-language).
+
 ## Adding a new language
 
 1. Xcode → Project → Info → Localizations → `+` (add locale).

scarf/scarf.xcodeproj/project.pbxproj

@@ -217,6 +217,9 @@
 				"zh-Hans",
 				de,
 				fr,
+				es,
+				ja,
+				"pt-BR",
 			);
 			mainGroup = 534959372F7B83B600BD31AD;
 			minimizedProjectReferenceProxies = 1;

scarf/scarf/InfoPlist.xcstrings

@@ -5,11 +5,47 @@
       "comment" : "Shown by macOS when Scarf first requests microphone access for Hermes voice chat.",
       "extractionState" : "manual",
       "localizations" : {
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Scarf verwendet das Mikrofon für den Hermes-Sprach-Chat."
+          }
+        },
         "en" : {
           "stringUnit" : {
             "state" : "translated",
             "value" : "Scarf uses the microphone for Hermes voice chat."
           }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Scarf usa el micrófono para el chat de voz de Hermes."
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Scarf utilise le microphone pour le chat vocal de Hermes."
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Scarf は Hermes の音声チャットのためにマイクを使用します。"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "O Scarf usa o microfone para o chat de voz do Hermes."
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Scarf 使用麦克风进行 Hermes 语音聊天。"
+          }
         }
       }
     }