fix(ci): address remaining review feedback

- Remove dead ci.Dockerfile (not referenced by CI workflows)
- Fix release.yml: all ubuntu-latest -> ubuntu-24.04
- Fix release.yml: JDK via apt-get instead of curl download
- Fix release.yml: hardcoded *** token -> use GITEA_TOKEN secret
- Fix release.yml: JAVA_HOME path consistency

.devcontainer/ci.Dockerfile

@@ -1,59 +0,0 @@
-# CI-optimized image for kryz-go-flutter
-# Build once on the runner host:
-#   docker build -f .devcontainer/ci.Dockerfile -t kryz-ci:latest .devcontainer
-# Then all CI jobs use this image — no SDK downloads needed.
-#
-# First build: ~30 min (downloads Flutter + Android SDK)
-# Subsequent builds: ~1 min (Docker layer caching)
-# CI runtime without image: ~40 min (redownloads everything per job)
-# CI runtime with image: ~2-5 min
-
-FROM --platform=linux/amd64 debian:bookworm-slim
-
-ARG FLUTTER_VERSION=3.44.0
-
-ENV FLUTTER_HOME=/opt/flutter
-ENV ANDROID_HOME=/opt/android-sdk
-ENV JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
-ENV PATH="${FLUTTER_HOME}/bin:${ANDROID_HOME}/cmdline-tools/latest/bin:${ANDROID_HOME}/platform-tools:${JAVA_HOME}/bin:${PATH}"
-
-# ── Layer 1: system dependencies ──────────────────────────────────
-# Stable layer — only rebuilds when package list changes
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    wget curl unzip git xz-utils zip python3 libgtk-3-dev ninja-build \
-    openjdk-17-jre-headless \
-    && rm -rf /var/lib/apt/lists/* \
-    && rm -rf /tmp/* /var/tmp/*
-
-# ── Layer 2: Flutter SDK (tarball, not git clone) ─────────────────
-# Tarball is deterministic — layer stays cached until FLUTTER_VERSION changes
-RUN wget -q "https://storage.googleapis.com/flutter_infra_release/releases/stable/linux/flutter_linux_${FLUTTER_VERSION}-stable.tar.xz" \
-    -O /tmp/flutter.tar.xz \
-    && tar -xf /tmp/flutter.tar.xz -C /opt \
-    && rm /tmp/flutter.tar.xz \
-    && chmod -R a+r ${FLUTTER_HOME}
-
-# ── Layer 3: Android SDK ──────────────────────────────────────────
-# Only rebuilds when cmdline-tools version changes
-RUN mkdir -p ${ANDROID_HOME}/cmdline-tools \
-    && wget -q https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip -O /tmp/cmdline-tools.zip \
-    && unzip -q /tmp/cmdline-tools.zip -d ${ANDROID_HOME}/cmdline-tools \
-    && mv ${ANDROID_HOME}/cmdline-tools/cmdline-tools ${ANDROID_HOME}/cmdline-tools/latest \
-    && rm /tmp/cmdline-tools.zip \
-    && yes | sdkmanager --licenses \
-    && sdkmanager "platform-tools" "platforms;android-35" "build-tools;35.0.0" \
-    && chmod -R a+r ${ANDROID_HOME}
-
-# ── Layer 4: Flutter precache (bakes platform artifacts into image) ──
-# Runs once — cached in the image layer
-RUN flutter precache --android \
-    && rm -rf ~/.cache/flutter/*/http_* \
-    && rm -rf /tmp/*
-
-# ── Layer 5: non-root user ────────────────────────────────────────
-RUN groupadd -g 1000 vscode \
-    && useradd -u 1000 -g 1000 -m -s /bin/bash vscode \
-    && chown -R vscode:vscode ${ANDROID_HOME} ${FLUTTER_HOME} /home/vscode
-
-USER vscode
-WORKDIR /home/vscode/projects