Add gzip-aware crash upload and OTA staging build/deploy tooling.

This restores the interrupted stash work on a dedicated feature branch, including backend decoding support, Dockerized build scripts, and staging channel artifacts for end-to-end OTA validation.

Co-authored-by: Cursor <cursoragent@cursor.com>

docker-compose.build.yml

@@ -0,0 +1,52 @@
+# Android Cast — Docker build + OTA staging publish
+#
+#   export OTA_BASE_URL=https://apps.f0xx.org
+#   docker compose -f docker-compose.build.yml run --rm android-build
+#
+# Outputs on the host: ./out/android_cast-latest.apk  ./out/ota/v0/...
+#
+# Publish APK only from an existing build (skip compile):
+#   docker compose -f docker-compose.build.yml run --rm ota-publish-only
+
+services:
+  android-build:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    image: androidcast-ci:latest
+    working_dir: /workspace
+    volumes:
+      - .:/workspace
+      - gradle-cache:/root/.gradle
+    environment:
+      OTA_BASE_URL: ${OTA_BASE_URL:-}
+      OTA_CHANNEL: ${OTA_CHANNEL:-staging}
+      GRADLE_TASK: ${GRADLE_TASK:-assembleDebug}
+      SKIP_NATIVE: ${SKIP_NATIVE:-0}
+      SKIP_TESTS: ${SKIP_TESTS:-0}
+      RELEASE_NOTES: ${RELEASE_NOTES:-}
+      OUT_DIR: /workspace/out
+    command: ["./scripts/ci-build-and-publish-ota.sh"]
+
+  ota-publish-only:
+    image: androidcast-ci:latest
+    working_dir: /workspace
+    volumes:
+      - .:/workspace
+    environment:
+      OTA_BASE_URL: ${OTA_BASE_URL:?set OTA_BASE_URL}
+      OTA_CHANNEL: ${OTA_CHANNEL:-staging}
+      APK_PATH: ${APK_PATH:-/workspace/app/build/outputs/apk/debug/app-debug.apk}
+      RELEASE_NOTES: ${RELEASE_NOTES:-}
+    entrypoint: ["/bin/bash", "-c"]
+    command:
+      - |
+        set -euo pipefail
+        ./scripts/generate-ota-v0.sh "$${APK_PATH}" "$${OTA_BASE_URL}" /workspace/out/ota-publish "$${OTA_CHANNEL}"
+        mkdir -p /workspace/out/ota
+        cp -rf /workspace/out/ota-publish/v0 /workspace/out/ota/
+        cp -f "$${APK_PATH}" /workspace/out/android_cast-latest.apk
+        echo "Published to /workspace/out/ota/v0/ota/channel/$${OTA_CHANNEL}.json"
+
+volumes:
+  gradle-cache: