fix(self-hosted): prevent Kong startup failures from CRLF line endings (#44422)

## What changed
- added `docker/volumes/.gitattributes` with `* text=auto eol=lf` to
enforce LF line endings for Docker-mounted volume files
- added a Windows troubleshooting warning to the self-hosting Docker
guide for Kong startup failures caused by CRLF line endings

## Why
Issue #44052 reports `supabase-kong` failing with `exec
/home/kong/kong-entrypoint.sh: no such file or directory`.
A common cause is CRLF conversion on Windows for mounted shell scripts.
Enforcing LF in `docker/volumes` prevents this class of failure for
fresh checkouts/copies.

## Validation
- `git check-attr text eol -- docker/volumes/api/kong-entrypoint.sh
docker/volumes/db/roles.sql docker/volumes/logs/vector.yml`
- `pnpm exec prettier --check
apps/docs/content/guides/self-hosting/docker.mdx`
- attempted `pnpm --prefix apps/docs run lint:mdx` (failed locally due
missing `node-pty` native module in this environment)

Closes #44052


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Added warning about Windows CRLF line ending issues with Docker
mounted scripts and resolution steps.

* **Chores**
* Added line ending configuration to enforce LF format in Docker
volumes.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Chris Chinchilla <chris@chrischinchilla.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

apps/docs/content/guides/self-hosting/docker.mdx

@@ -198,7 +198,7 @@ Access to Studio (Dashboard) is protected with **HTTP basic authentication**.
 
 <Admonition type="danger">
 
-    A secure password MUST be set before starting Supabase. The password must include at least one letter - do not use numbers only or any special characters.
+  A secure password MUST be set before starting Supabase. The password must include at least one letter - do not use numbers only or any special characters.
 
 </Admonition>
 
@@ -236,6 +236,12 @@ To stop Supabase, use:
 docker compose down
 ```
 
+<Admonition type="caution" label="Windows: CRLF line endings">
+
+  If the API gateway (Kong) fails to start with an entrypoint error, your local files may have been checked out with CRLF line endings instead of LF. Re-clone the repository, or normalize everything in the `docker/` directory to LF, then restart Supabase. Fresh clones should already use LF because of `.gitattributes`.
+
+</Admonition>
+
 ## Accessing Supabase Studio (Dashboard)
 
 By default, you can access the dashboard through the API gateway on port `8000`.

docker/.gitattributes

@@ -0,0 +1,17 @@
+* text=auto
+
+*.md eol=lf
+
+*.env eol=lf
+.env.example eol=lf
+
+*.sh eol=lf
+*.sql eol=lf
+*.yml eol=lf
+*.yaml eol=lf
+*.ts eol=lf
+*.exs eol=lf
+*.conf eol=lf
+*.tpl eol=lf
+Caddyfile eol=lf
+Dockerfile* eol=lf