Trim static Qt builder layer

ober

6aa4a37a3f8ed62493783f894d780f5c60b9abcf

diff --git a/Dockerfile.qt b/Dockerfile.qt
index 46cccb5..0044012 100644
--- a/Dockerfile.qt
+++ b/Dockerfile.qt
@@ -20,8 +20,6 @@ ARG JERBOA_SOURCE_URL=https://git.sr.ht/~lisp/jerboa
 ARG JERBOA_SOURCE_COMMIT=ae716feb376ce9adefcad65e923ebfd866131947
 ARG JERBOA_SOURCE_TREE=9fafa4b48f6a4d1c166dc3ae57be720237ee988b
 ARG JERBOA_SOURCE_NATIVE_FEATURES=tls,crypto,postgres_feat,wasm
-ARG JBROWSER_SOURCE_COMMIT
-ARG JBROWSER_SOURCE_TREE
 ARG APT_SNAPSHOT=20260701T000000Z
 
 ENV DEBIAN_FRONTEND=noninteractive
@@ -69,6 +67,8 @@ RUN JERBOA_SOURCE_COMMIT="$JERBOA_SOURCE_COMMIT" \
     jerbuild --version && \
     jerbuild --jerboa-home >/dev/null
 
+ARG JBROWSER_SOURCE_COMMIT
+ARG JBROWSER_SOURCE_TREE
 COPY . /src
 WORKDIR /src
 
@@ -95,7 +95,10 @@ RUN make vendor-adblock vendor-fuse vendor-yubikey && \
     tar tzf "$tb" | grep -E '/SOURCE-SHA256\.txt$' >/dev/null && \
     bin_path="$(tar tzf "$tb" | grep -E '/bin/jerboa-browser\.bin$' | head -n 1)" && \
     tar xzf "$tb" -O "$bin_path" > /tmp/jerboa-browser && \
-    file /tmp/jerboa-browser
+    file /tmp/jerboa-browser && \
+    cd / && \
+    rm -rf /src /root/.cache /root/.cargo/registry /root/.cargo/git \
+      /tmp/jerboa-browser
 
 FROM ${BASE_IMAGE}
 COPY --from=builder /out/jerboa-browser-static-qt.tar.gz /out/jerboa-browser-static-qt.tar.gz