docs: expand i18n section with supported languages and translation guide

README.md

@@ -75,7 +75,23 @@ Expand **Or paste a token manually** and enter a bearer token from your Indiekit
 
 ### Language
 
-The plugin follows Obsidian's display language. Set it in **Settings → About → Language**. Currently supported: English (`en`), German (`de`).
+The plugin follows Obsidian's display language automatically. Set it in **Settings → About → Language**.
+
+| Code | Language |
+|---|---|
+| `en` | English |
+| `de` | German |
+
+#### Adding a translation
+
+1. Copy `src/lang/en.ts` to `src/lang/<code>.ts` (e.g. `pt-BR.ts` → use code `pt`)
+2. Translate every string value — keep all `{placeholder}` tokens unchanged
+3. Register the locale in `src/i18n.ts`:
+   ```ts
+   import { pt } from "./lang/pt";
+   const locales = { en, de, pt };
+   ```
+4. Open a PR — translations are always welcome
 
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@@ -222,6 +238,10 @@ src/
   IndieAuth.ts          PKCE IndieAuth sign-in via GitHub Pages relay
   SettingsTab.ts        Obsidian settings UI
   SyndicationDialog.ts  Pre-publish dialog to select syndication targets
+  i18n.ts               t() helper — locale detection and string lookup
+  lang/
+    en.ts               English strings (source of truth, 63 keys)
+    de.ts               German strings
 ```
 
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