fix: redirect ignoring --route-prefix for .pbf tile requests

[Paritoshcodes]

Fixes #2596

Ensure redirect URLs include the configured route prefix when handling
.pbf tile requests behind a reverse proxy.

Previously the redirect logic constructed URLs without the route prefix,
causing incorrect redirects when Martin was deployed behind a reverse proxy.

This change prepends the configured route prefix to the redirect
Location header.

A regression test was added to verify correct behavior.

[Copilot]

Pull request overview

Fixes a redirect bug in Martin’s tile endpoints where requests to *.pbf (and other *.{ext} tile routes) produced a Location header that ignored the configured --route-prefix, breaking deployments behind reverse proxies.

Changes:

• Include SrvConfig.route_prefix when building the redirect Location for tile redirects (preserving query string).
• Add an integration test asserting the redirect Location includes the configured prefix for .pbf tile requests.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
martin/src/srv/tiles/content.rs	Passes route_prefix into the redirect helper so Location includes the configured mount path.
martin/tests/route_prefix_test.rs	Adds regression test verifying redirect Location includes the route prefix and preserves query params.

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[CommanderStorm]

Thanks for the bugfix! 🎉

[c-meier]

Shouldn't the same thing be done for the pluralization redirect handlers (styles→style, sprites→sprite, etc.) created by #2528 ?

And, if I understand the doc correctly, the base_path config parameter can also change the Location of the redirect for the tile api.

[Paritoshcodes]

Hello @c-meier, that is a good point but my fix currently only handles the .pbf redirect path, but I agree the same logic may need to be applied to the pluralization redirect handlers as well. I can take a look at that after this PR is merged if needed.