fix: Bug - No android app icon

agents-docs/LESSONS.md

@@ -25,6 +25,13 @@ Durable rules for AI agents working on this project. Read this file at session s
 
 ## Lessons
 
+### Generate Android brand icons from the source mark; guard against stock Capacitor placeholders [mobile] [android] [assets]
+
+- **Trigger:** the Android app shipped the default Ionic/Capacitor launcher icon (and a white adaptive background) because no brand icon was ever generated into `toju-app/android/app/src/main/res/`.
+- **Rule:** regenerate launcher + splash from `images/icon-new-rounded.png` with `npm run cap:assets:android` (`tools/generate-android-app-icons.mjs`, uses `sharp`), set the adaptive background to brand purple `#4A217A` (never `#FFFFFF`), and have the adaptive icon reference `@mipmap/ic_launcher_foreground` PNGs (delete the stock `drawable-v24/ic_launcher_foreground.xml` vector). `cap:sync` is not needed — these live in the native project, not `webDir`.
+- **Why:** a native launcher icon can't be asserted through a browser, so the regression proof is a hash guard: `mobile-android-launcher-icon.rules.ts` records the SHA-256 of every stock placeholder and the tests fail if any density still matches one. Pixel checks (purple ring + white-cat centre) confirm the brand mark actually rendered.
+- **Example:** `findStockCapacitorResources(hashByFile)` must return `[]`; unit `mobile-android-launcher-icon.rules.spec.ts` + e2e `e2e/tests/mobile/android-app-icon.spec.ts` (deterministic fs/pixel checks, no emulator).
+
 ### Bind chat attachments to a pre-allocated message id, never by matching content [attachments] [chat] [mobile]
 
 - **Trigger:** caption-less media (videos/images sent with no text) grouped onto the message bubble above and left an empty message below on Android — `ChatMessagesComponent` dispatched `sendMessage` without an id, then a `setTimeout` re-discovered the message by `entry.content === content` (always `''` for attachment-only sends) and called `publishAttachments` on it.