Release: multi-container Docker gateway API forwarding (#6917) (#6995)

* feat(docker): enable gateway API and password forwarding in compose files

- Added API_SERVER_KEY forwarding to enable the gateway API listener in multi-container setups.
- Configured HERMES_WEBUI_PASSWORD to ensure password authentication works as expected.
- Updated documentation to clarify API_SERVER_KEY requirements and forwarding behavior.
- Added regression tests to cover the new functionality and ensure proper configuration.

* build(docker): force LF line endings for shell scripts via .gitattributes

A CRLF shebang (#!/bin/bash\r) breaks locally-built Docker images: the
kernel can't resolve the interpreter /bin/bash\r, so 'docker compose up
-d --build' on Windows with core.autocrlf=true fails with
'exec /hermeswebui_init.bash: no such file or directory'. The repo blobs
and CI/GHCR builds are LF and unaffected; only Windows local builds
baked the CRLF checkout into the image.

* fixup(docker): dedup API_SERVER_HOST after rebase onto #6968 (which already added it)

* docs(changelog): stamp #6917 (multi-container gateway API forwarding)

---------

Co-authored-by: Yang <yang_qwq@qq.com>
Co-authored-by: nesquena-hermes <nesquena-hermes@users.noreply.github.com>

.gitattributes

@@ -0,0 +1,10 @@
+# Normalize line endings to LF in the repository.
+* text=auto
+
+# Shell scripts must stay LF on checkout too. A CRLF shebang (`#!/bin/bash\r`)
+# breaks the Docker image: the kernel can't find interpreter `/bin/bash\r`, so
+# local `docker compose up -d --build` on Windows machines with
+# `core.autocrlf=true` fails with `exec /hermeswebui_init.bash: no such file
+# or directory`.
+*.sh text eol=lf
+*.bash text eol=lf