Add: OpenTTD 15.0-rc1 announcement (#364)

Co-authored-by: stormcone <[email protected]>

Author: michicc

_posts/2025-12-08-openttd-15-0-rc1.md

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+---
+title: OpenTTD 15.0-RC1
+author: michi_cc
+---
+
+Good things come to those who wait. OpenTTD 15 is starting the final lap with first release candidate!
+
+With a release candidate, the focus shifts from adding new features to finding and fixing bugs to make OpenTTD 15 the best OpenTTD yet.
+The finding part is where you, the players, come in, too. If there's anything you notice, head over to our [issue tracker](https://github.com/OpenTTD/OpenTTD/issues/new/choose) and make a report.
+
+If you've already played any of the betas and use the OpenGFX baseset, you might have noticed a message about missing sprites. This is due to some of the new features in OpenTTD 15. We recommend switching to the newer (and still updated) OpenGFX2 baseset, which you can easly get via the in-game content downloader.
+
+Some notable changes over the previous beta3 release are:
+* Automatic font loading for characters not part of the normal language files (like e.g. player names or chat messages)
+* Signs, waypoint and station names may be moved
+* Terrain generator can make wetlands for rivers unable to reach the sea
+* Island maps and heightmaps can be surrounded by infinite water instead of black
+* Bridges can now be built over locks and docks, too
+* Various tweaks to interface scaling
+* Improvements and fixes to badge support
+* [NewGRF] Support for trains with multiple rail types
+* A variety of bugfixes
+
+As always, see the changelog for the full list.
+
+* [Download](https://www.openttd.org/downloads/openttd-releases/testing.html)
+* [Changelog](https://cdn.openttd.org/openttd-releases/15.0-RC1/changelog.md)
+* [Bug tracker](https://github.com/OpenTTD/OpenTTD/issues)