refactor(discord): remove rich presence and bundled SDK

Remove the presence setting, platform bridge, SDK archive, and SDK preparation from local and CI builds. Reject leftover Discord native libraries in release APK audits.

.github/workflows/ci.yml

@@ -66,10 +66,6 @@ jobs:
               - 'scripts/build_rust_backend.sh'
               - 'scripts/check_backend_apk.py'
               - 'scripts/test_check_backend_apk.py'
-              - 'scripts/prepare_discord_sdk.py'
-              - 'scripts/test_prepare_discord_sdk.py'
-              - '.github/actions/discord-sdk/**'
-              - 'third_party/discord/**'
               - 'lib/**'
               - 'assets/**'
               - 'pubspec.yaml'
@@ -231,20 +227,10 @@ jobs:
             "cmake;3.22.1"
           echo "ANDROID_NDK_HOME=$ANDROID_HOME/ndk/29.0.14206865" >> "$GITHUB_ENV"
 
-      - name: Test Discord SDK preparation and APK audits
+      - name: Test APK audits
         run: |
-          python3 -m unittest discover -s scripts -p 'test_prepare_discord_sdk.py'
           python3 -m unittest discover -s scripts -p 'test_check_backend_apk.py'
 
-      # Fork PRs do not receive SDK decryption secrets. They still compile the
-      # optional debug bridge and run native tests, but never produce a release
-      # APK with the advertised Discord feature silently missing.
-      - name: Prepare pinned Discord SDK
-        if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
-        uses: ./.github/actions/discord-sdk
-        with:
-          passphrase: ${{ secrets.DISCORD_SDK_PASSPHRASE }}
-
       - name: Get Flutter dependencies
         run: flutter pub get
 
@@ -264,18 +250,16 @@ jobs:
         run: gradle -p android :app:assembleDebug :app:testDebugUnitTest
 
       - name: Build Rust release application
-        if: env.SPOTIFLAC_DISCORD_SDK_DIR != ''
         run: bash scripts/build_android.sh --target lib/main.dart
 
       - name: Verify Rust release APK payloads
-        if: env.SPOTIFLAC_DISCORD_SDK_DIR != ''
         run: |
           python3 scripts/check_backend_apk.py \
             build/app/outputs/flutter-apk/app-arm64-v8a-release.apk \
-            --backend rust --abis arm64-v8a --require-discord
+            --backend rust --abis arm64-v8a
           python3 scripts/check_backend_apk.py \
             build/app/outputs/flutter-apk/app-armeabi-v7a-release.apk \
-            --backend rust --abis armeabi-v7a --require-discord
+            --backend rust --abis armeabi-v7a
           # PR builds use Gradle's test key; production signing stays in Release.
           for abi in arm64-v8a armeabi-v7a; do
             "$ANDROID_HOME/build-tools/37.0.0/apksigner" verify --verbose \