Fix jwt error in admin UI (#8140)

* add jwt token in weed admin headers requests

* add jwt token to header for download

* :s/upload/download

* filer_signing.read despite of filer_signing key

* finalize filer_browser_handlers.go

* admin: add JWT authorization to file browser handlers

* security: fix typos in JWT read validation descriptions

* Move security.toml to example and secure keys

* security: address PR feedback on JWT enforcement and example keys

* security: refactor JWT logic and improve example keys readability

* Update docker/Dockerfile.local

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Chris Lu <chris.lu@gmail.com>
Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

docker/Dockerfile.local

@@ -4,6 +4,7 @@ COPY  ./weed /usr/bin/weed
 RUN chmod +x /usr/bin/weed && ls -la /usr/bin/weed
 RUN mkdir -p /etc/seaweedfs
 COPY ./filer.toml /etc/seaweedfs/filer.toml
+COPY ./security.toml.example /etc/seaweedfs/security.toml
 COPY ./entrypoint.sh /entrypoint.sh
 
 # Install dependencies and create non-root user