firefox, waterfox: let the neko user own the profile root (#718)

`mkdir -p /home/neko/.mozilla/firefox/profile.default/extensions` (and
the same for `.waterfox`) runs as root and only `profile.default` was
handed to the neko user, so the directories above it stayed root-owned.
The crash reporter of current Firefox (158 in the 3.2 images) keeps its
reports and Glean store in `.mozilla/firefox/Crash Reports`; after a
browser crash it cannot create that directory and exits with

  failed to acquire Glean store: Os { code: 13, kind: PermissionDenied, ... }
  (toolkit/crashreporter/client/app/src/send_ping.rs:51)

or, in auto-submit mode,

  Failed to create directory (/home/neko/.mozilla/firefox/Crash Reports/pending): Permission denied

so no report survives. Verified on firefox:3.2.0 by running the reporter
against a main-process minidump: it fails as shipped and creates
`Crash Reports/{glean,pending,events}` once `.mozilla` belongs to neko.
Waterfox builds its profile root the same way and gets the same fix.

The other apps are fine: the base image chowns all of /home/neko, the
Chromium-based ones and remmina only COPY --chown files into it,
tor-browser chowns its whole /opt install.

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

apps/firefox/Dockerfile

@@ -40,7 +40,7 @@ RUN set -eux; apt-get update; \
     #
     # create a profile directory
     mkdir -p /home/neko/.mozilla/firefox/profile.default/extensions; \
-    chown -R neko:neko /home/neko/.mozilla/firefox/profile.default; \
+    chown -R neko:neko /home/neko/.mozilla; \
     #
     # clean up
     apt-get clean -y; \

apps/firefox/Dockerfile.nvidia

@@ -18,7 +18,7 @@ RUN set -eux; apt-get update; \
     #
     # create a profile directory
     mkdir -p /home/neko/.mozilla/firefox/profile.default/extensions; \
-    chown -R neko:neko /home/neko/.mozilla/firefox/profile.default; \
+    chown -R neko:neko /home/neko/.mozilla; \
     #
     # clean up
     apt-get --purge autoremove -y xz-utils; \

apps/waterfox/Dockerfile

@@ -17,7 +17,7 @@ RUN set -eux; apt-get update; \
     #
     # create a profile directory
     mkdir -p /home/neko/.waterfox/profile.default/extensions; \
-    chown -R neko:neko /home/neko/.waterfox/profile.default; \
+    chown -R neko:neko /home/neko/.waterfox; \
     #
     # clean up
     apt-get --purge autoremove -y xz-utils bzip2; \