Fix VICE cross-compile and image cache-warming for release builds

build-image/Dockerfile: add bison (VICE's configure needs a yacc-compatible
parser generator, same category as the earlier flex fix) and exclude
packageRelease/signReleaseBundle from the cache-warm stage's gradlew run,
since those always fail there for lack of a keystore that's never baked
into the image.

vice_jni.c: guard getFrameCount()/setSoundEnabled() with #ifdef
HAVE_VICE_SRC like their sibling functions already do — they referenced
globals that only exist when VICE is linked in, breaking the documented
no-VICE placeholder build. Only surfaced now because the cache-warm stage
is the first thing to ever compile this file without VICE.

dist.sh: floor the untagged dev-build's versionCode at 1, since the
0.0.0-dev+<sha> placeholder otherwise computes to 0, which Android's
Gradle plugin rejects.

run-image.sh: wipe generated build artifacts (vice-src, vice-libs,
nibtools-src/libs, app/build, .cxx) before each run so it exercises a true
from-scratch build like CI does, instead of silently reusing artifacts
left over from a previous local run. Also chown the bind-mounted repo back
to the host user on exit, since the container runs as root and was
otherwise leaving root-owned files behind.

dist.sh

@@ -74,6 +74,9 @@ fi
 [[ "$VERSION" =~ ^([0-9]+)\.([0-9]+)\.([0-9]+) ]] \
     || fail "VERSION '$VERSION' is not a semantic version (expected X.Y.Z, optionally with a -pre+meta suffix)"
 VERSION_CODE=$(( ${BASH_REMATCH[1]} * 10000 + ${BASH_REMATCH[2]} * 100 + ${BASH_REMATCH[3]} ))
+# Android requires a positive versionCode — the untagged dev placeholder
+# (0.0.0-dev+<sha>) would otherwise compute to 0 and fail Gradle configuration.
+[ "$VERSION_CODE" -gt 0 ] || VERSION_CODE=1
 echo "Version: $VERSION (Android versionCode $VERSION_CODE)"
 
 # Patch versions into the tracked source files for this build only, then